Would it be illegal to sell those shirts for a profit? (assuming the Badmovies.org logo wasn't on them...which would require Andrew's approval)
Do they violate copyrights?
Some would, some wouldn't. Since it's a purely commercial enterprise, you wouldn't have any Fair Use rationale to use copyrighted stills. You could use stills from any film that's in the public domain. Also, Andrew's quotes are copyrighted, so you'd have to get permission from him for those as well.
Of the films you chose, I'm pretty sure HOLLYWOOD CHAINSAW HOOKERS and FLASH GORDON are copyrighted, and I believe FASTER p***yCAT is too. Not sure about the others, but there's a good chance they are copyrighted.