I’d pick NU over WashU in a heartbeat IMO your choice is between UCLA and NU. Both excellent schools so no wrong choice. There is no getting around that it’s cold in Evanston in the winter and we definitely have all four seasons. Only you can decide if that’s a deal breaker.
Yes, it is difficult for non music majors to have opportunities here, but I don’t think marching or pep band is that restrictive. Probably depends on what instrument you play. Can you reach out to admissions to ask if you can speak to a student in the marching band to ask about their experiences?
I have a family member at NU now, who is pre med, and having a great experience. Small classes, great advising, and facilities. She loves the ease of double majoring and minoring. She’s always busy socially and not involved in Greek life.
Hope this helps. Congrats on excellent acceptances!