I don’t think this is a productive exercise. Most liberal arts colleges have strengths in all of their programs of study, and besides, it’s not like you are choosing a graduate program in which you will specialize in something specific. You are choosing an undergraduate college for a well-rounded liberal arts & sciences education. All of these colleges are strong places with good reputations where you will get a great education. I’m not sure why a word-association exercise with people who are passingly familiar with a handful of the colleges would matter.
There are some colleges that do have great programs in specific areas - like Middlebury’s foreign languages program or Lafayette’s engineering, which is unusual at a small LAC. But that doesn’t mean that they aren’t good for other areas.
The question about what differentiates these colleges is a different one - and, I think a more productive one more likely to yield information that can be useful to you. A student with strong interest in languages might prefer Middlebury, for example. If your son has lots of interests and wants flexibility within a curriculum to design his own area of concentration, Amherst has an open curriculum and Hampshire is designed for that kind of inquiry. Washington & Lee tends to be a more conservative LAC. A writer would love the intensive writing across the curriculum program at Hamilton (and Hamilton also has a level of curricular freedom, with fewer core/distribution requirements that allow more flexibility in planning one’s own course of study. So do Bard, Colgate, Vassar, and Wesleyan, which aren’t on your list.)