I think this idea is really neat.

So, how does the shuffle work exactly? Do you redistribute the assets separately or as a group? How would you like to receive assets that consists of multiple files?

Since we're sharing assets, I think it is a good idea to require the application of a license to them, to clear up any future confusion. For example, the Creative Commons license. This also requires attribution, so people would need to know which asset came from whom.

I think the assets create shoud be C0 (public domain) to avoid any issue.
About the shuffling : I was going to take all the files, and distribute each elements randomly.
I can rename the files so the author is specified, but then I fear that at the game, players wouldn't see who made the assets.

Ok, it's in the mail!