Based on what The Skating Lesson I would guess Firebird. The pieces of music that I think of when Evan is mentioned are Firebird, Scheherazade, Rhapsody in Blue and Carmen. Of the three that overlap with Miki, Firebird is the only one I really associate with her. She used it in three different seasons including her last competitive one and its the music she used when she sort of landed a quad sal and won the junior world title.
If that is the choice of music for Gracie, it doesn't immediately strike me as an obvious or exciting choice for her, but I'll hold my breath until I see the program. I'll still hold out hope that they start looking to the Nicole Bobek canon. Nicole had lines for days that I think both Frank and Lori are into, and they both have a natural buoyancy.
I could totally imagine Gracie skating to this music, plus it would be a nice classical piece I don't remember hearing since '98, save for the part with Mao's old music of course!
https://www.youtube.com/watch?v=FblGVzjzxO0