I don't remember my parents being so concerned about sleepovers.
Maybe instead of asking the parents things, you should ask your daughter about Aubri. What kind of girl is she? I think you could learn a lot about the parents by the way Aubri behaves.
I mean, what would you ask the parents? I doubt it'll be a co-ed sleepover, but you could ask. I would assume the parents would be in the house the whole time, but it's probably worth double-checking. Maybe about any activities that are planned?
When I was in 4 grade and up, the preferred party was a sleepover (if you couldn't have a pool party). Some we just hung out around the house, pigged out, giggled together, ran around the house and generally drove the parents nuts. Sometimes we had actual activities - I remember going to a haunted house for one. I think we did ice-skating one time, etc.
I guess I've always wondered when I see questions like these: what do you think will happen? This girl has survived as long as yours has, why would that suddenly change because of a sleepover? One night of being allowed to do something your daughter normally isn't won't affect her long-term.
I guess I just don't get it. My daughter is only 18months, so maybe I'll understand when it's her turn to do sleepovers, but I just don't remember them being that big of a deal when I was younger.
Maybe you're at a loss for questions because there really isn't anything else you can ask that will be that big of a deal...