Adding a vote for St. Olaf!
I’m a current freshman and it checks all the boxes you listed (small classes, good stem, good financial aid). Our core classes are humanities/analysis heavy (language, religion, social science, power and race, first years have to take a writing and rhetoric course, etc.) but, honestly, it seems to be a big benefit. We have really good grad outcomes and I’m sure that it’s in part due to the fact that everyone’s exposed to college level writing and literature analysis.
The campus is very friendly and there are a lot of spaces for LGBTQ students (myself included); there’s a not-insignificant number of students who are openly trans in all years.
I can actually speak to the first-year research thing: it’s not super common, but there are professors willing to take on first years who are passionate about doing research. We also have a year-long class called Molecular Discovery (which I’m in!) that revolves around a microbiology research project. You don’t apply for it, it’s just first-come-first-serve when you fill out your advising form. This is the inaugural year!
Classes are pretty small—my biggest is 45 people, and that’s a Chem lecture. My other classes are 18-24 people. The professors I’ve interacted with (both instructors of mine and not) are super friendly and really want to meet students who are excited to learn.
I will say that I don’t know how good our CS department is. The Bio department is very good and the Math department is too (although our Math major is a little unconventional), though.
Also, the campus is gorgeous! And the food’s pretty good.