just because a game is free doesn't make it legal. They can still sue for damages and more likely send a you a cease and desist as soon as any hype builds up regarding the end of the game.
Either get proper permision form the company that is in posesion of avatar or make an 'avatar inspsired' game (use differant names/items but keep the same kind of theme)
Or just use your creativity instead of relying on leaching off somone elses ideas!
__________________
Gamma | OnRPG Troy (40 : 20) | SwiftSteel |