I think it would be weird not to have letters from your most recent academic institution. Sure, have a letter from someone who knows you well from Community College. But you are not applying to medical school from CC, you should have something... anything from your current University faculty.
My professors know me well and I never attended a CC. What's important is standing out. Participate in lecture for example, attend office hours, etc. If you can stand out of a large classroom (50+ students), it shows how good of a student you are.
It would depend on the quality. If it was too much time between the CC and the university I'd question why you couldn't befriend anyone at your university. With all the stiff competition I'd want to have the least amount of questions..
quality > recency if within the past ~5 years. you'll be fine, especially with the PI letter.
also as someone who came from a UC, I understand how it's difficult to even get close enough to a professor to ask a question (those 40+ students trying to get the professor's attention after a 600-person lecture are difficult to navigate around).
If the community colleges know you much better and can say much better things than your university professors definitely ask them for the rec instead. Quality is so important. I wouldn't want some cliche rec.