But, from experience and IMO, for items 1 and 2, you are already too late.
If you are that serious with publishing your efforts commercially, hire a lawyer now familiar with the entertainment/game IP domain. And, as opposed to robobrain's position, I say get your all your paperwork going now, rather than later. For example, early registration of copyright entitles the registrant a) presumption of copyright validity and 2) statutory damages.
Line up your legal ducks now, like copyrights, trademarks, NDA on collaborators, etc., because if the money starts rolling in, you find that some people you thought you knew, you didn't. It happens.
PS: There are entire books on this.