I would compare the course curriculum for each school first. See which CS electives are available and if any of the schools have a specific area of interest you would like to pursue.
Location will be very different for each school. SCU and UCSC have great proximity to SV so a great benefit for internships.
CPP is mainly a commuter school like most of the Cal states but in nicer area of the city of Pomona. You have to venture a few miles for restaurants and entertainment and there is not a really reliable transportation system, so you will need a car.
UCR has a nice campus but some area’s near campus can be questionable. It is in the inland empire and can get very hot during the summer. It is a stark constraint in scenery from UCSC.
All schools will give you a good education, will offer many opportunities for you to succeed if you take advantage so it may come down to costs and personal preferences.
Watch some YouTube videos of the campus tours to get a feel for the campus life.
I am proud CPP graduate and loved my time there but that was many many years ago. I was a commuter but had several friends living on-campus and they were satisfied with your education and social life.
Best of luck with your decision.