NEC and Juilliard don’t even ask for test scores, they do get your academic transcripts (I didn’t know Peabody asked for test scores, they do), Curtis asks for the SAT I have never heard of anyone getting rejected because of test scores at Curtis, though. Programs like NYU and USC are music schools within a larger university and those kind of schools generally look closer at test scores and grades, and while they generally IME give music students a break compared to what academic admits would need to get in ie instead of 3.9 would accept a 3.5, not care about AP classes and so forth, it still is a standard.
NEC and Juilliard don’t ask for standardized tests and won’t look at them, and I believe the same is true of most of the other stand alone schools (Peabody is an exception). With grades, from what the admissions people told me they only look at them to make sure the person isn’t a total screw up who couldn’t handle theory and such, they definitely don’t care about AP tests,etc and they don’t have a “to get in here, you need a 3.x and above” that you have at the universities, it is more like “geez, this guy has failed all kinds of classes, no way they could handle theory”.