How to resolve disagreement with project teammates over which professor to work with?
To expand the comments above into an answer: ask the professors what they think is a good idea, ideally both at the same time (e.g., at the end of a class where they are both there).  You have less chance of coming off as disrespectful, since you approach from the perspective of a student desiring guidance.  If they say you should work with both, then that's probably a fine plan to follow as well.