This was a fantastic summary and (having lived in the Midwest, East, and South, with the shortest period in the Midwest at 6 years) it rings true to me.
I would add that the other difference that I have observed between the student body of the different regions’ schools (more recently) is (1) the number of students planning on going into finance/consulting. Some of those students everywhere, but seems more at the NE schools. My children found the “where they go” pages on school websites to be very useful; and (2) it seems the midwest schools are struggling to diversity their student bodies in comparison to comparable NE LAC’s, and their resulting strategy is to admit even more international students.