UF and FSU are big party schools, but my friends that go to both of those, aren’t really big party people, so they have their own clubs and groups that they join. Politically, UF and FSU are a tad bit more conservative than liberal but its not a huge problem. UF is a stronger engineering school and FSU is better for international relations and politics. Again the party culture exists and both schools have a massive undergraduate population, so if that’s big turnoff, I would definitely recommend somewhere else.
If your son is big on studying politics and studying abroad, I would definitely add Georgetown University to the list. Georgetown has a lot of solid study abroad programs and their programs in public policy and international relations. Undergraduate enrollment is under 5,000 but its honestly would be a perfect environment for a fellow introvert. 32 ACT would be in the middle 50% too.
Carnegie Mellon is really solid in engineering and the hard sciences. A lot of the kids their get the rep of being introverted and finding their own groups, so your should fit right in. In terms politics and international relations, they’re not really well-known for that so his interests might align to the university if he decides to not continue engineering.
George Tech is really solid too and has a renown engineering program. It would certainly broaden his horizons to learn from a top 5 undergraduate engineering program.
You could also a add a few ivy in there if that’s okay with you like Cornell and Dartmouth. And schools like Boston College which has a solid Jesuit culture. With a 32 ACT, its pretty good and lot of of the elite universities can be considered matches. I would definitely look at universities in the northeast that tend to be a more liberal.
Anyways, best of luck in your college search and I hope you and your son finds the best university that fits your interest the best!