My impression of a few of the CA schools you mentioned:
I attended CSU Stanislaus. The Greek Life there is very small (no greek housing) but I loved the personal attention and I felt the school really supported Greeks coming to campus, because we are such a positive influence. As small as the greeks are on the school, the school is small too, so it fits. In the quad between classes, you will always find greeks sitting together in the sun or playing volleyball.
Plus its a lovely park-like campus with new dorms.
I dated a guy from CSU Fresno (and my best-friend went there). Compared the Stanislaus, they have a "real" greek system with lots of parties and houses. We always had a great time there on exchanges, though it got a bit wild at times.
It's really hot there.
My husband attended UC Davis and was in a fraternity but found that the school in general is very academics based, so there was more studying then partying going on. It was sometimes hard to pull people away from homework to get them to do fun stuff. But this could have just been his impression. It is a beautiful area with a great downtown and EVERYONE is into saving mother earth.
Those were the schools that I know about. Good luck with your decision.