First, I suggest you go to the music forum and post this. Also read “The Double Degree Dilemma” essay that is posted near the top of that forum.
You can do a BA with a general music major, without a listed major in composition, if you so choose, and still develop enough to get into a top grad school for composition. In fact, you can even major (at Harvard, “concentrate”) in something else entirely, take lessons, have pieces played, do summer programs, and still get into grad school for composition.
You can also double major, major/minor or do a double degree. Harvard and Tufts have double degrees with NEC (for Harvard it is a BA/MM), and Yale has a fairly recent double degree with its own School of Music. Princeton has an exchange with the Royal Academy (I believe- check). Brown actually has a composition strand to the music major (along with MEM/technology and ethnomusicology). Columbia also has an excellent program.
Look at Oberlin’s BA and Bard’s programs as well, though you should, for the most part, avoid schools with conservatories/BM programs in case the best teachers and opportunities go to BM students.
Check how undergrad pieces are played. At Harvard, students have their own association/collective and hire an outside group once a year, and use Harvard musicians for other concerts. There are indeed excellent musicians at all these schools, especially those with double degree programs I think.
I would include Tufts, Vassar, Sarah Lawrence, Williams, Amherst…
One thing to think about: Brown and Amherst, maybe others, have freer curricula without gen eds which can appeal to some.
Make sure to choose schools with the usual criteria, such as cost, size, location, and “vibe.”
I’ll PM you.