It’s too bad you/she resist the Midwest. A lot of diversity in the different states. Some excellent flagship U’s and top notch math and CS options. I look at the list of the many schools you mention and do not see the elite ones for math or CS. btw- it’s Purdue, a public U in Indiana (ie Midwest).
She should look at grad school rankings for fields she is interested in to get an idea where schools fall. Good undergrads will take grad level courses. Top ten or closer to top one hundred? Math and computer science have overlapping courses- crosslisted in both departments. Think of computer engineering as hardware and computer science as software. Some schools only do majors- one could double major in math and CS for example.
Your list is all over the map. Be wary of schools touting their departments. She will need to make lists of many factors and prioritize them. She seems to already have eliminated several top schools in the fields of interest as they are in the Midwest. Her current stats suggest she is a good student but not extraordinary (might not be MIT material…).
Consider size of departments in any given school. Ten versus one hundred in a major may mean huge differences in course offerings and professor depth. Many, many factors.