the only possible chance of a KH character bieng in the roster is sora or roxas not more than 1 characters from a franchise remember?
" One hypersonic brainwave scrambler, scrambled"
Clank from R&C: ACIT
If it's any KH character, it'll be Sora. Tetsuya Nomura stated that Sora will always be the lead of the Kingdom Hearts series and he'll only end when the series ends. Therefore, the one who would represent the Kingdom Hearts series would be the main protagonist and so would be Sora.
Check out my team's RPG, Legena : Union Tides
Have you seen the Red Sky? And the Green Lightning?