Besides submitting a portfolio, etc. is it the norm to reach out to conductors or music teachers at Harvard?
The music supplement should include recordings or video (check on this), a music resume and letters from teacher(s)/director. My kid also asked if admissions would like a cue on the recording for the best 3 minutes so they didn’t have to listen to the whole thing 
We reached out to the music department only after acceptance, at which point it was easy to arrange attendance at classes, meetings with a teacher etc. The music department also had an open house.
Some people here on CC have indeed reached out to conductors, directors and professors, before applying or before acceptance. Personally I think it is better if you have questions and are ascertaining whether to apply, rather than trying to make a connection to help you get in. But that’s me.
I suggest you post this on the music forum as well. It is found under the “majors” section.