Sora,Terra,Ven,and M. Xehanort connection?

Okay so i was talking to my brother about this and we came up with this theory.


Terra was at one point normal until M. Xehanort came along. at the end of the scene with his yellow eyes we assumed he was affected by the powers of darkness. he then lost his heart to it or his memories and could only remember the name xehanort. then went to ansem the wise and you know the rest of his story.

M. xehanort, we guessed that he went into kingdom hearts for some reason He, Ven and aqua disappeared.
Sora's Anti-form is related to both M. Xehanort and Terra i think but how i can't guess. Terra and Sora were somewhat related like a friend or role model whatever.
the reaseon roxas looks like ven and can dual weild keyblades has to do with sora and ven. we also guessed that roxas's looking like Ven has something to do with the unknowns.

any reactions to this