Listed below is who I think should play the following original characters. In parentheses is the creator of that character.
Tobin Bell as Harrison (Villain84)
Whoopi Goldberg as Tiana (Villain84)
Jack Black as Oscar (Villain84)
Grey DeLisle as Chloe (Villain84)
Fred Tatasciore as Carnage (Villain84)
Brad Garret as Bruiser (Villain84)
Mark Hamill as Pete (Villain84)
Marc Silk as Duke (Villain84)
Richard Steven Horvitz as Roger (Villain84)
Kyle Fairlie as Joey (Villain84)
Jerry Trainor as Milo (Villain84)
Kari Wahlgren as Chelsea (Villain84)
Ryan McPartlin as Rocky (Villain84)
Wes Bentley as Black Fang (Villain84)
Ned Beatty as Savage (Ari141)
Aaron Eckart as Buck (Ari141)
Dante Basco as Aatu (Ari141)
Zach Tyler Eisen as Sean (Ari141)
Jessie Flower as Emily (Ari141)
Bill Nighy as Fenrisulfer (Ari141)
Sam Worthington as Justin (Lancewing)
Yvonne Strahvski as Sara (Lancewing)
Steve Buscemi as Cain (Lancewing)
Robert De Niro as Cassius (Lancewing)
Donna Murphy as Sheba (Lancewing)
Zach Tyler Eisen as Wildfire (Lancewing)
Chloe Moretz as Madi (Lancewing)
James Woods as Balto (ThatPersonYouProbablyDon'tKnow)
Sam Worthington as Deimos (Frontier Productions)
Tilda Swinton as Scar (WitlesstheSmall)
Johnny Depp as Edward McTarvish (Battleshiplip)
Bill Nighey as The Stranger (Battleshiplip)
Tim Curry as Nuka (StarswordIsCool)
Dave Wittenberg as Tom (StarswordIsCool)
John Goodman as Jeremy (StarswordIsCool)
Wayne Knight as Lance (StarswordIsCool)
David Cross as Trepex (R0xas The Destroyer of Worlds)
Carolyn Semour as the Alpha Wolf Spirit (Roxas The Destroyer of Worlds)
Mandy Moore as Chloe (CGWolf'13)
Ron Perlmen as Redrum (Rain Wolf '91)
More upcoming. I'm open for suggestions.