SAT scores mean very little. There are a lot of very smart kids who don’t have stellar test scores. My daughter attended a large college where her scores were in the bottom quartile. After she was there about a month I asked if she was finding it hard to compete with the other students and she said she was pretty sure she was in the top one-third academically, and that she was amazed at how many students there were with super high test scores who just weren’t all that smart. Perhaps an artifact of the test-prep industry, and the wide gulf between a multiple choice test and college exam and writing expectations. (My DD ended up graduating summa cum laude, which at her school meant essentially top 5% GPA – so she proved to be correct in her assessment. Turns out that self-discipline and drive are the most important factors, and there aren’t any tests to measure that. )
Anyway, depending on the college, your son may go off to school and be quite surprised at to find that he is not at the intellectual advantage over other students that he expected.
However, the bigger problem I see in the plan is “small” LAC. Does this school have adequate resources if your son decides to change focus or majors? What about that desired major and uncommon minor he likes? Who teaches those courses, and how many professors are there? If a professor goes on sabattical your son’s junior or senior year, is that going to throw everything off track? or if it turns out that he is not fond of a particular professor, will there be the ability to complete the major with different classes?
My son, who had very high test scores, did attend a small LAC – and ran into problems, but not because of the caliber of the other students. It was a combination of lacking the discipline his sister had, and also the small part. Too small coupled with the schools’ commitment to small discussion size classes meant that it was often difficult getting desired classes-- either the course wasn’t offered that semester or it was full up and he had to settle for something else to fill his schedule. Ultimately the college wasn’t able to meet his needs as he matured and his interests evolved.
So have your son visit and sit in on classes in his desired major. Count up the number of faculty in departments of interest; look at a current course schedule to get a sense of how many classes are actually offered each semester; and learn what you can about the faculty. It’s not the other students and their test scores that matter; it is the resources the college has to offer.
Some small LAC’s are fine, and some have consortium or cross-registration agreement with nearby colleges that allow them to provide greater resources to their students --so it is something you have to specifically research, not a generalization that applies to all LAC’s.