As far as school events taking precedence, ask if they have a district flow chart in place. If they don't I would always say that State>Area(Region for sports)>Region (Area Sports)>District>Concert>Scrimmage/Practice. More importantly on a question like that I would really want a candidate to speak of finding ways to 'make it work.' Maybe scheduling isn't ideal, but sometimes we roll with the punches. Speak especially on you having communication with other coaches directly and keeping kids out of the middle of it.
NAfME has a decent sheet of possible interview questions here: https://nafme.org/wp-content/files/2016/01/Download-Interview-Practice-Questions.pdf
Depending on the district if it's just a principal be ready to answer more questions on classroom management and how you differentiate instruction. Those seem to be the big ones when they don't know much about your content area.