Yuffie

Battle in any forest in the world and she’ll show up. You have to defeat her and after you do, talk to Yuffie as follows:

Yuffie: “You spikey-headed jerk! One more time, let’s go one more time!”

Answer: Not interested

Yuffie: ‘You’re pretty scared of me, huh?!”

Answer: …….petrified

Yuffie: “I’m really goona leave! REALLY!”

Answer: Wait a second

Yuffie: “You want me to go with you?”

Answer: ………..Thats right

Yuffie: “All right! I’ll go with you!”

Answer: ………..Let’s hurry on.

Vincent

Unlock the safe in the Shinra Mansion and fight Lost Number. The safe’s code is right 37 left 10 right 59 right 97. After winning the battle get the basement key in the safe. Now go down to basement and talk to the center coffin (don’t go the the library). Vincent will come out and talk to him about Sephiroth and after that, he’ll return to sleep. Wake him again and get him to tell you his name and he’ll go back to sleep. Head towards the stairs and he’ll join you.