I lean toward NU because its social scene is far better than WashU’s (which you mentioned you had concerns about). I also think Chicago >>>> St. Louis, plus you would be close to some family in Milwaukee. Big picture they are equal caliber as you said.
I do think pre-med will be a grind at all these schools if you go that way (I would recommend none of them for pre-med to be frank)…you will likely get better advising, prof contact, research and clinical opportunities at NU and WashU than UCLA.