Since this was my son’s main interest too, I will comment on some of the schools we personally visited.
When you go on school visits, I highly recommend that your kid contact the FSAE club before the visit (look them up online)! In every case, they were happy to meet with my son and show him around! It was VERY eye opening for him to see each club’s garage / workspace, and to talk to the students.
Oregon State – this is one of the most advanced FSAE teams in the US and IMHO, it is worth a visit if possible, just to see their workspace and learn about their cars. My son says that they are also welcoming to new team members and have a well developed training / mentoring process. Lots of things to like about this school for a ME student. From your current acceptance list, my son would 100% pick this one (and would also choose it over many other schools on your list), but everyone has different priorities.
U of Washington – my son chose not to attend this school because it was such a difficult / competitve process to join the FSAE team that he thought he was unlikely to get to participate. The team itself is strong but they do not accept many applicants.
Cal Poly SLO – my son did not actually expect to like this school as much as he did, but when he visited, he loved seeing their workspaces and talking to students. Hands-on is a real thing at CPSLO, not just a buzzword.
UC Davis – a great school with an up and coming FSAE team! They were struggling a bit with garage space when my son visited but I gather that has been worked out now. Worth a visit if accepted.
UCSD – good school, has FSAE, but note that it is very difficult to switch into ME if you are not admitted direct to the major.
UC Santa Cruz – they do not have an ME major (yet?) but Formula Slug seems to be a great up and coming FSAE team.