They will probably cover it all but here are some things that you could consider asking:

school policy on bullying
class sizes
number of classes in each year
teacher retention rates (usually a good sign of how the school is going - but hard to ask directly - maybe something like "so how long have you been here")
extra activities - like music lessons, sporting teams, excursions etc

But mainly it will be just a getting to know you sort of thing. Nothing to stress about at all.