Not sure what your asking; nothing is removed. Think of transferring units as a two-track process. At a UC you need 180 quarter-units to graduate for most majors. A UC will give you up to 70 semester units (105 quarter units) towards UC graduation from classes you’ve taken anywhere else. At the same time you have a set of classes you must take depending on your college and major. UC gives you subject credit for everything you’ve taken, no limit. The links I gave have more info.
I understand wanting to be around students that take school more seriously. You may be able to find such students by taking part in the premed club, doing honors clubs/programs that are available, etc. In a large public you only need to find a dozen or so kindred spirits to completely change your experience.
Next, nothing they do at Cal is going to prepare you better for the MCAT. The MCAT tests knowledge of lower-division math/science classes you’ve likely already taken. The way to prepare for the MCAT is to use review books and practice, perhaps also take a prep class.
Unless you are aiming for a MD/PhD then research isn’t that important for med school admission. It was 30 years ago, but these days its just another factor to consider. What is important is that you continue spending time volunteering in a health-care setting, perhaps also look for shadowing opportunities.
SFSU has a premed advisor that you should be working with if you aren’t already since you have at least 1 more year there, there are books about how to succeed in premed, also you can find online sources such as the very informative https://www.rhodes.edu/sites/default/files/PreMed_Essentials.pdf and https://www.amherst.edu/campuslife/careers/gradstudy/health/guide