Between my two kids I looked at about 30 schools. I don’t believe there is another school that is quite close to U Chicago, but there are lots of schools that share aspects of it. Our daughter is enrolled at U Chicago and potential schools that she considered if she didn’t get in included Wash U, Williams, and Colgate. Lots of others but those seem to be the closest overall.
Someone mentioned looking at schools with special honors programs and I think that is also a valid approach. If your son is at U Michigan or Elon or Villanova or other places with honors programs, there may special housing and special programs for your son. The students he would interact most frequently with would be like him.
I live in Chicago and Hyde Park most certainly is urban. This is what urban life is like in Chicago unless you live in the Loop.
I do think you should be thinking about schools at this point. Maybe not talking about them though in order to avoid stress. For both of my kids, we starting seeing schools the summer before Junior year - a solid week of touring. This was a combination of places they thought they were interested in and places that I thought might be a good fit. The overall vibe, the weather, whatever can help them understand what they do and don’t want. We saw a couple of schools during Junior year and then did another weeklong tour the summer after Junior year. My son couldn’t decide between two for ED, so he went back and sat through classes at both early in his senior year and that made it clear to him what was best. While all colleges now have virtual this and that, these experiences are highly managed and in some cases do not reflect the experience(s) that my kids had visiting the schools in person.
With the significance of ED and REA, you son really needs to know what he wants before his senior year begins. If he plays a fall sport or has other significant time commitments during the fall he needs to also have his Common App and at least some of the college specific essays done before school starts. During COVID when schools dropped the test requirement, they discovered they didn’t have enough information about students. Last year my daughter encountered additional optional essay questions (as many as 4 for 1 college), optional videos, and optional resumes in addition to the optional interviews and optional test scores. The pressures will be tremendous if everything is left to the last minute. (Please know that Williams has supplemental nothing, not even one essay, which may be why so many athletes and legacies end up there).
To diffuse the stress, I spoke about the importance of safeties and liking them as well. She applied to 3 so she could have options if it came to that. She also applied to a number of “I’m pretty sure I’ll get in but in today’s environment, I don’t know” schools. And then she applied to top schools. It was a lot of applications, but this is what she wanted and it all worked out for her.
Good luck.