DeeDee and ABQ, I love your stories.
DD's aunt and uncle with Asperger's are musicians/composers, piano (aunt) and piano/drums (uncle). I hear DD's uncle hated mandatory piano lessons, fought tooth and nail, then went back to it on his own terms and became a composer (what your DS's teacher was anticipating, ABQ?).
A bunch of us on both sides of the family sing. I was in choir from 4th - 12th grade and loved it, so I know exactly what you are talking about, DeeDee, regarding self regulation.
We attended a free mommy and me music class today and DD was bouncing off the walls. In between times, she was experiencing the music with her whole body. We are also going to sign her up for dance and/or gymnastics. I understand acting is a great tool for Aspies, for social scripting. She loves acting!
In general, DD is full on Arts Girl.