Exactly. One daughter attended a high school that does not offer any AP classes at all. She was accepted to every university she applied to, and got merit aid at most of them.
If you like orchestra, then I too would stick with orchestra.
Do you get grades all along? If you get to see your grades, I do not see what is gained by having the schools compute your GPA. You can see how you are doing in your classes.
Universities do not expect you to fix your high school. They expect you to do well at whatever high school you attend.