I tend to have a mental image of a college family tree, with branches that are closer or farther to each other in a multi-dimensional space.
Anyway, for medium-sized private core curriculum colleges very strong in humanities and social sciences in big-metro locations (what I would see as a common description of Chicago and Columbia), I would immediately be thinking in terms of Jesuit colleges. So many of them ALSO fit that sort of description, and fall along a broad range of selectivity.
True residential college systems are pretty scarce, it is a very expensive model. But you could check out options as diverse as SUNY Binghamton and the Claremont Colleges, or maybe the BiCo (Haverford and Bryn Mawr), or even Five Colleges (I guess Four now? RIP Hampshire).
Vassar and Wesleyan I think of as particularly academicky LACs. There are SOOO many of those, again at a wider range of selectivity, and indeed merit opportunities. But this is the sort of list I think can include womens’ colleges (as appropriate), Carleton, Grinnell, Haverford, Oberlin for some, Macalester, Kenyon, Whitman, forum favorites like St Olaf and Kalamazoo, Hendrix, and so on.
Emory, Vanderbilt, and WashU to me are all examples of how elite families outside the Northeast wanted to create their own Ivy-style universities closer to home. Thinking broadly, that actually includes institutions like Stanford, Chicago, Duke, and Northwestern. Also the aforementioned Rice. Wake Forest, Rochester, and Case Western. Maybe CMU, although it has a more distinctive format. From there, I think you can go in some different directions. Arts and Sciences sorts of kids might well want to consider some of the highly-resourced LACs. Some kids might want to look again at Jesuit colleges, starting with Georgetown and BC in fact. Maybe some of the publics that have a bit of an unusual history and format, like William & Mary, Miami of Ohio, or perhaps even Pitt.