Lol, and here I was about to start thinking heavily about Josh not being a playable character.
Anyway I know most of the characters you can unlock, they are:
Chris - Stars
Chris - Not sure what costume it is, but you get at least 2 Chris characters with the 1 already available.
Sheva - Same as above, she gets 2 other characters aside from the 1 available, unsure of what they are though
Jill - BSAA
Jill - Battle Suit (When she's under Weskers Control)
Wesker - Stars
Wesker - Midnight (As he is when you fight against him with Jill)
Anyway thats all I know, and I know that getting 40000 points with different characters will unlock a new character depending on the character you use.
Credit to .Impact for the sig & avy