Delta has a major hub in Minneapolis-St. Paul. They have non-stop flights from there to Los Angeles as well as to dozens of cities on the East Coast. You can combine both schools on the same itinerary by purchasing a round-trip ticket to LAX with a stopover in MSP. There normally shouldn’t be a big price difference between that and flying only to Los Angeles or Ontario. If you still have to drop one, I’d probably say drop Pomona. Carleton is less of a reach and, while all the schools satisfy your criteria to various degrees, Carleton generally seems the best fit, at least on paper.
Carleton, my alma mater, has a long reputation for being queer friendly (it’s actually one of the reasons I applied there, back in Dark Ages). If you haven’t done so already, check out the Gender and Sexuality Center and talk to the staff and students there on your next visit. I’ve also seen Carleton on various lists of queer-friendly campuses.
Carleton also has a long-standing reputation for being granola, very liberal and politically active (Paul Wellstone taught here). From the most recent CIRP freshman survey data I can find (2015), 76% of incoming students identify as either liberal (58%) or far left (18%) while 20% identify as middle of the road and about 4% identify as conservative. Less than 1% identify as far right.
Carleton is “laid back” in the sense that people generally don’t care what you look like, what you wear, what your GPA is, etc. Students and professors are on a first-name basis. Academically intense while also extremely casual. I never wore anything other than shorts and T-shirts and sandals to class during springtime. Jeans and T-shirts during cooler weather. Add flannel shirts during winter. I remember they sent out a memo during my graduation week saying something like, hey, we know this is Carleton, but could you guys please put your shirts on when you visit the president and his wife in the garden reception at Nutting House (the home of the college president).
As for bio and chem, note that Carleton is about to build a new science facility. It will probably be completed by your senior year of college. In the mean time, the facilities that were housed in Mudd Hall are being temporarily moved to the former Music & Drama Center.