Oh, write the game anyway, just don't attempt to make any money and let what will be, be.
Personally I would strongly recommend AGAINST such a strategy. Not making money out of a possibly IP-infringing project does not protect you from prosecution AT ALL. There are enough IP holders and lawyers out there who would pursue any infringement, no matter if there is money involved or not.
Even worse, with no revenues, any prosecution will hit you much harder.
All in all, considering the massive amount of work that goes into developing a game (even a non-commercial one), I would take the additional time it takes to generate IP-free artwork. If artwork is very important to you, it would be a good idea to associate with an artist or find open source artwork.