Physician here. Public Health is its own field, it should be done by those who want that knowledge, not as a jumping off point for medical school. There are physicians who add the MS in the field, not a BS/BA level degree, for various reasons. Forget Public Health unless that is your planned career.
Your long post is a bit confusing. It is a great idea to have an undergrad major that interests you. There is no reason to have a science major for medical school unless that is your primary interest. The only reason to add that is because you already have so many of the needed credits that it is easy to complete along with your primary (comp lit) major. See an above post- physicians do have nonscience majors. They teach you what you need to know to become a good physician in medical school- there is no reason (outside of time and interest) to learn material ahead of time.
You also need to look at your science gpa to date and your competitiveness for medical schools. You need to have a plan B since most who consider medical school either change their mind or are not accepted. You need to consider your priorities. WHY be a physician? Etc.
Any school will do for medical school, if you do well on the MCAT and have high grades plus the other current criteria. You need to consider which school will give you the courses you want in your comp lit major. It is good for future physicians to indulge in a college education for its sake and take all sorts of classes unrelated to medicine- especially since there won’t be time for them in medical school and many years beyond. MCAT material can be studied independent of classes.
You give a jumble of ideas in your post. You need to move beyond your CC. Both UC Irvine and UCLA require you to make an adjustment so forget the perks you have had. You need to succeed at a four year U. Both schools are in the same area (think beyond your narrow definition), they are not even in different parts of a large state. I have visited both counties enough times to know how similar they are even if you point out differences.
Finances matter hugely. All money that can be saved for medical school will be needed. Figure out the cost differences. Include tuition/fees/books, room and board, transportation, sundries. Saving money for the goal of being a physician trumps the cachet of UCLA over Irvine.
Most of us do not get to go to our dream school. UCLA means something to you at your age and where you live in S CA. You saved money thus far by attending a CA CC instead of spending it on one of the four year schools. You also gave up the experiences and education of one of many excellent CA schools. You will not be getting the college freshman experience so that is not a factor.
The reason to choose UCLA over UC Irvine is because it offers you a better education in your chosen major of comp lit. You need to look at the courses required and available in the major at both schools. You can offer this as justification for choosing UCLA, assuming there are not huge cost differences you and your family would struggle with (remember how expensive medical school is).
Take time to organize your priorities. Perhaps medical school/becoming a physician is not the direction you should go. Look at where a comp lit degree would lead you.