Kimahri theme, the theme of Mt. Gagazet, the song is suitable for a determined person like me, followed by Yuna's Theme in Besaid.

I don't remember all of them have a theme, I'll try:

Tidus: 'This is my story'
Yuna: Besaid theme
Wakka: 'Blitzoff'
Lulu: Don't know? Calm Lands theme?
Auron: Auron Theme
Rikku: Rikku Theme
Kimahri: 'People of the north pole'
Seymour: Seymour Theme
Jecht: Otherworld?

I don't know I created some of it anyway.