Why would you post this in a forum for Crusade, SSF2's largest rival?
EDIT: And the character voices and roles need criticism anyways.
Mario: How would he not be Italian?
Sora - He's around 16.
Ness - He's 14.
Link - Link sounds nothing like an Englishman.
Megaman - Megaman is a young boy IIRC.
Kirby - Have you never heard "poyo" or "hai"?
And in addition, a lot of these characters already have voices of which your descriptions would change completely. Heck, all characters in the antagonist side are actually good-spirited, save for Wario, but at that he's just a greedy glutton.
Tell me: Why?