I can’t speak to the specific schools on your list, though perhaps @arewethereyet.24 might have some insight on Skidmore?
If your son has a clear #1 that has remained consistent and that is affordable for your family, and he doesn’t care about seeing what other options may be available (and at what price), then I can understand the desire to ED. If that is not the case, however, then I would be wary of applying ED as seniors in high school are often known to change their minds.
As you indicated in your original post, so many schools say the right things before a student applies. But how is it once your son’s accepted and is looking for particular accommodations? Are they supportive and suggesting additional accommodations that could help him succeed, or are they trying to explain why most of your list should be eliminated? This is another reason why I’d be hesitant about submitting an ED application in your son’s case.
I’ll second @tsbna44’s suggestion to ask to be connected to current students receiving supports to see what their experience has been like, not just with the office of disabilities, but also with the professors (are the professors generally understanding, or do students repeatedly have to get the disability office’s help to have professors fulfill what are in the letters given to the professor at the start of course?).
Maryland’s McDaniel College has a reputation for offering great supports for its students. This page is marketing material, but I find that this consortium’s profile pages do a nice job of giving a better sense of a school than most websites: McDaniel College – Colleges That Change Lives
But apart from a liberal arts college, what is your son looking for from his college experience? Additionally, are there any schools on his list where he would be happy to attend, that are affordable for your family, and where he is extremely likely to be admitted? If not, finding those schools should be a priority.