You know what you have to do - just collect all others and the ocean is yours!

Cave of the Seven Stars is the optional dungeon that you can access when you reach final save point in Revorse Tower. From the save, keep going south until you reach a room where you can use teleporter. Go east and when you reach the room with 4 doors, go south and on teleport. You will reach a room where you need to go through west door. Save and beat the dungeon for the trophy. I was level 125 when i did this.

This is game's strongest optional boss which is recommended for the end.
One of your characters has to learn Music Specialty and level it up to 10. Also, you need to have Listening and Rhythn Sense talents with that character. I recommend Millie.

Then you need to buy the Silver Trumpet. You can buy the Trumpet in Tropp or Eckdart. After you have it, start composing. You should create "The Devil's Aria" pretty soon. If you have issues, buy the Music Editor from Santa in Silvalant city for 100000 Fol.

When you visit Tatori, you can find Puffy next to Inn. You need to finish her role-playing game with correct answers to beat her at that game. 

Star Ocean First Departure R - Puffy's RolePlaying Game

You unlock Voice Gallery when you recruit a character and save your progress on final save in final dungeon.

4 characters are not missable: Roddick, Ilia, Ronyx and Millie
9 characters are optional (Mavelle can be swapped, so if you take that into consideration, you can get 5 optional characters per playthrough).
You will need 2 and a half playthroughs to actually have all of them as your playthrough party - and visit the final save to save those.

Saving on final save point in the game will record your overall progress, which means you can then start new game (as there is no new game plus) and unlock what you miss.

For the best strategy, check trophy guide overview at the top.

You need to press switches in Labyrinth of Champions in certain order. I did this at the end because you can reach this place from last planet.

Automatic Story Unlock.

Worst trophy ever.

IMPORTANT NOTE: You cannot get this ending if you did 3 PA's for Ronyx and Illia's love ending.

So, this one is actually simple if you know exaclty what is the requirement. I'm still not 100% sure but i'm 95% sure because it unlocked for me during some testing.
The idea is to have at least 9 AL (Afinity Level points) towards Roddick from ALL party members. Many guides say that you need to have 9 from only the past Roak members, which is wrong (past members are Ashlay, Phia, Ioshua, T'nique, Welch, Erys, Cyuss, Mavelle, Pericci).

My party of the past Roak members was Ashlay, Phia, Ioshua and Erys.
Before last boss in the Reverse Tower, you can play with AL by using Publication Super Speciality - "A super specialty where everyone contributes to an amazing book that they can all be proud about publishing."
Specialties needed: Writing and Machinist
Skills needed: Penmenship (Writing) and Machinery, Operation (Machinist)

Create a book with Roddick using that, a give that book to party member to raise his AL towards Roddick to 8 (if its 6 it raise, if its 10 it lowers). Have in mind to do that only for those which have it lower than 8. In the final battle, you can use up to 3 members for which you want to raise AL by 1 after beating both versions of final boss (just don't let your members be dead after killing the boss).

With all that in mind, having at least 9 AL towards Roddick from all party members unlocked this secret ending after all ending scenes are over. Also, wait until both credits are done, there is a secret scene at the end after which trophy unlocks.

Star Ocean: First Departure R - AL (Affection Levels) Guide

Alternate route, by Expelsword:

"I can confirm doing exactly the following works:
Party of 4 + Ioshua, Erys, Ashlay, Pericci.

Before Asmodeus:
Have all characters read each Published book (Make 8 with each character, and give them all one).

Fight Asmodeus using Roddick, Ioshua, Perrici, and Ashlay as your party; make sure they all are alive at the end.
Fight Revorse using Roddick, Ilia, Millie, and Erys; make sure they all live."

Old Race Ruins is the optional dungeon and Ancient Guardian is the boss of that dungeon. Defeat it for the trophy. 

To get inside the ruins, leave Silvant and travel northwest hugging the northwest mountain until you reach almost the end of continent. Just when you circle around the mountain, you will enter the ruins.

Star Ocean: First Departure R - World Maps

When you first visit Tatori, you can just go north and find arena. Just left of entrance is counter where you can participate in arena matches. 

Well, you need to beat all matches from rank H, G, F, E, D, C, B, A (1 match per rank). Beating H unlocks G and so on.

Star Ocean: First Departure R - Easy and Fast Level Up Guide

Star Ocean First Departure R - Easy Fast Level up Guide plus Gabriel

SFT are essintially your techniques, but upgraded. You need to pick up some to actually upgrade your technique by using it combining with your character Proficiency. For this trophy you only need to obtain SFT items, not learn the skills itself. 

Recruit Ashley, Ioshua, Phia, Mavelle. You need to get Phia before you get Millie (which will happen in Silvant City if you have Ioshua). So, make sure that after starting the emblem quest you go directly back to Astral to get emblem there, plus you can ask Phia to join as you will have 6 slots at that point.

You will need Phia for Gods of War SFT and Ashley for Wyrm King SFT. Check details on link bellow.

Star Ocean First Departure R - Secret Fighting Techniques (SFT)

Automatic story unlock at the top of Mt. Metorx.

Automatic story unlock.

When you enter Tropp you'll see something crash on the planet. After that you will need to go back to Kraat, and just next to Kraat you can find the crash site.

Mt. Eckdart is directly to the northeast of Eckdart. When you do your business in Eckdart, you can leave and visit Mt. Eckdart. Additionaly, if you have Ioshua, he will comment about old man there who saved him.

Visit Mt. Eckdart, just follow the path until you reach the cabin. In the scene, select "Let's take them out!" for positive points and you can sleep here for free. The mission is to go north from cabin, kill ALL enemies that you see (no random encounters, just visible enemies), and report back to Foster (the old man). That will unlock the trophy. Note that Roddick comments when you kill last monster, so it should be easy do know when you are done.

Automatic story unlock.

Defeat boss in Labyrinth of Champions.

Automatic story unlock.

From Haute entrance to Mt. Metorx, close to entrance you can find entrance to Abandoned mine (just aside from a rock shape). Defeat the boss at the end.

Automatic story unlock.

In Van Y Ille, after you beat Labyrinth of Champions, the king will give you first emblem and you will start the emblem quest. After collecting all 4, the trophy unlocks.

Automatic story unlock.

Automatic story unlock.

Automatic story unlock.

Cyuss first appears when Roddick and Ilia appear in Haute. Go into the item shop, talk with the item shop owner, Badam, select "I'd like to talk" option. Go to the bottom part of Haute (just where you entered the town) and talk to the "Weapon Master". Say you would like to buy the sword for 20 fol, and Cyuss will intervene. Now, back to Item store for some more talking.
Cyuss joins the party temporarily. Go accross Mt Meteorx to Portmith, get the goods from the weapon shop in Portmith, and return to Haute. At the end of the quest, you will get the option to keep Cyuss or not. Choose "Ask him to join you" to recruit Cyuss.

If you get him you CANNOT get:
Phia early (you can still get her later on)
Ashley
Erys

If you didn't recruit Cyuss, you will meet Phia first at Auantim, where she offers to escort the party to Tatroi. The choice here does not mean it will join/not join now or in the future for real. There are basically 2 ways to recruit Phia.

If you failed to get Both Ashlay and Cyuss
There will be an event in Astral, in which Lord Lias is injured by the fake Phia will result in Phia being jailed. Go to the castle and spring Phia from jail,
and after completing the caves, she will join you. If you recruit Phia this way, you CANNOT get her final SFT.

If you have either Ashlay or Cyuss
This time Phia will not join during the assasination event. You can get her just after getting first Emblem in Van Y Illie. You MUST have up to max 6 characters in your party to get her. If you have more, you can't get her. Return to Astral after getting the first emblem and visit Castle entrance and ask her to come.

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

Ashlay appears in the arena in Tatroi if you did not recruit Cyuss. Enter arena, go right, up the stairs, left, down the stairs and there he is. Talk to him to leave. Clear one rank match with Roddick. Go to docks (right side before the entrance to arena).

Be careful, if you enter Astral Cave (left from Tatroi entrance) and go to Astral that way, you will not be able to get him. You must go to docks to get him. You need him to get Erys.

If you get him, you cannot get Phia early in the game, but you can still get her later.

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

After clearing the Astral Cave and beating Darth Widow boss inside, you will get some rewards from the king. Next step is either to go to Purgatorium or explore other town. If you don't go to Purgatorium as your next destination, you will NOT be able to get Ioshua.

So, make your way to Purgatorium (northwest of Tatroi is an intersection, west leads to Tropp, while other way leads to Purgatorium. You need to enter there from behind (not the front you will see, go circle around the mountain and you will enter from the back. In here, you will meet Ioshua. You need to finish Purgatorium after you exit, you need to choose "Stop him." and "Could you join us?" to recruit him. Be careful, Stop him option is second option, do not hit X like crazy, you can select wrong option.

You need Ioshua for Erys.

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

Mavelle first appears along with Ronyx/Millie on the Van Continent (inside town Ionis). In order to recruit her, you must have either Ashlay or Ioshua or both in your party. After a night of drinking, she will join automatically.

If you recruit Mavelle, and she is your 7th character (you only have one slot left), you cannot get:
Phia late-game
T'nique

You need Mavelle to get Erys.

Ditching Mavelle (happens only if you have Ioshua in party):
Yes, you can replace her with Erys. This happens after Silvant (when you get emblem there). You need to enter Old Race Ruins, beat boss there and side with Ioshua which will make Erys join and Mavelle leave.

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

To even get Erys, you need Ashlay, Ioshua and Mavelle in your party. You can read in related trophies how to get those.
After getting emblem in Silvant, you can enter Old Race Ruins (northwest of Silvant) and explore until the depths. Down there you will witness a scene. Siding with Ioshua (2nd option) will make Mavelle leave and you will get Erys instead.

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

You can get him just after getting first Emblem in Van Y Illie. You MUST have up to max 6 characters in your party to get him.

Visit Tatroi (you need to travel a bit from Van Y Illie) and participate in arena matches until rank D. In 5th battle of rank D, T'nique will fight against you. Beat him and you will recruit him.

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

In Portmith, after initial item quest with Cyuss (after choice to recruit or ditch Cyuss), go to port and talk to upper left pirate. First choice will get you to Pirate Hideout where you need to beat the boss. After the scenes, visit 3rd door from the right to left in prison where catgirl is playing ocarina. You will automatically appear in Portmith and catgirl will run off. Pick up Ocarina (you MUST get this, missing this item means you cannot get Pericci later).

Once the Emblem Quest starts (in Van Y Illie), return to Kratus (the First village) and start a Private Action (square button when on the map close to town). Talk to Millie, and choose Pericci when given an option of 3 names in the conversation. Equip Roddick with the Orcarina, and play it near the cat. Pericci will then join if you have 7 or less characters (8 is the max).

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

To recruit Welch, you must make sure you have the Silvant Emblem, which you acquire during the Emblem Quest. Then, from the town of Ionis, go in the direction of Van Y Illie city. Eventually, you will reach an area on the world map with two briges. Head to the forested area to the west between the two bridges and navigate
through it to find a house. This is the Welch's hut.
Choose the first option to get Welch. She will only join if you have 7 or less characters in your party (8 is the max).

Star Ocean First Departure R - Character Recruitment Guide (How to get all characters)

To witness the Ronyx and Ilia ending, you must initate a series of private actions.

First step is to return to Haute after you recruit Ronyx and Mavelle. Approach Millia and Illia on the bridge during PA to initiate a scene.
Second step is to talk with Ronyx and Illia inside the bar in Tropp during PA.
Later in the game when you visit Eckdart, approach jewelry shop and watch a scene with Ronyx and Illia druing PA. This should be enough for this ending. Now beat the game and witness it.

All steps needs to be done before completing the Demon World (that is the point of no return to past Roak).

If you go to Inventory and under Status (down a bit there); you can find Talents and list of talents some character has. Using Skills -> Specialties, you can "awake" another Talent. For example, if you don't have Listening, use Music specialty to compose songs using istruments until Listening unlocks. Or, you don't have Rythm Sense, use Music and perform learned songs until it unlocks.

Star Ocean: First Departure R - Specialties

You can buy Tr-Emblem in Silvalant. Enter Silvalant, go a bit west (not on the next screen). Behind the tree in front of the house is Santa the dealer. Price? Only 8000765 Fol.

Star Ocean: First Departure R - Easy Fol Guide

You will unlock every movie apart from the last 3. To even unlock them, you must save at the final save before the final boss. 

To unlock last 2 movies, you need to go south from final save point (all the way south from teleport with which you arrived on final floor). You will soon enter a room that has many doors. Enter west door and save at that save point; that will unlock last 2 movies.

Now, the 5th movie. That is is only obtainable at Old Race Ruins where you can get Erys, IF you DON'T have Ashlay. You MUST have Ioshua and Mavelle. That triggers the movie. Save, go to main menu, check if all movies are there - trophy unlocks.

You need to witness Private Action event involving Pericci and Roddick. This means you need to recruit Pericci as one of your team members. Make sure to pick Ocarina after Pirate's Hideout at beginning of the game (which is required to get Pericci).

Location: Portmith - Castle Entrance; Inside the Muah Treasury.
When: After recruiting Pericci and recieving the Muah Emblem (after beating boss in the Muah Treasury).
Solution: Talk with Pericci and choose "Oh well...lets give it a shot".

This will now open another Private Action between Roddick and Pericci. Now initiate second PA.

Location: Haute, outside Item Shop
When: After above Private Action.
Solution: After the event on location above, talk to Pericci next to Haute Item shop and you are rewarded with Bunny Whistle.

You need to learn all Specialties (like Alchemy, Music etc.). Check the guide topic for list and requirements for them all (Special Specialties are not needed for this trophy).

Star Ocean: First Departure R - Specialties

You need to buy all different types of skill sets in skill guilds. Check link bellow for details and which towns holds which skill sets.

You will need:
Combat 1
Combat 2
Combat 3
Knowledge 1
Knowledge 2
Knowledge 3
Sense 1
Sense 2
Sense 3
Technical 1
Technical 2
Technical 3

Star Ocean First Departure R - All Skill Sets and Guilds Guide