OF COURSE!
Heh.
No way would Nomura make a new character. I mean, Totally, completely unconnected and original-to-their-debut-game characters? Off the top of my head, KH1 has Kairi, Sora, Riku and ASD, KH2/CoM/Days has the Orgy (minus Roxas, Xion and Xenmas) and DiZ/Ansem, and BBS has Eraqus...