Are there any games with more than two characters in Theatrhythm?
When you complete a song in Theathrhythm, there's a Title Character bonus of +30 Rhythmia for each character in your party who is from the same Final Fantasy game as the song. If you unlock a second character from the same game, you can use both, for +60 Rhythmia.
Are there any Final Fantasy games for which you can unlock a third or fourth character from the same game?
Actually, there are two Final Fantasy games which have three characters appear in Theatrhythm:
Final Fantasy IV:
- Rydia (green shards)
- Kain (navy shards)
Final Fantasy VII:
- Aerith (red shards)
- Sephiroth (black shards)
All other games have two characters, except Dissidia, which has only one character, Cosmos (rainbow shards).