Parents / Student's that push you around do not have the best interest of your program and will never be satisfied.
Offer your assessment of what is best for for your program and all students. If they don't like it they can leave.
You wouldn't have a parent tell the AD to require their kid to be a starter. It's nonsense and pointless drama.
Do what's best for your band kids and build them up. Kids will resent a teacher that let's students push them around and not hold their standards.