I reached out about being waitlisted at one of my top choices. My notification was from a POI so I emailed them back. I said in the email that it was my top choice and that I would appreciate any information they were able to offer. They ended up telling me the number on the waitlist, which doesn’t do much, but having a little bit of information helped. I think it’s fine to reach out, but I wouldn’t count on gaining a ton of insight. Best of luck; I know the feeling!