I think it is good to have 3-4 questions in mind. Our experience with this type of visit was that the coaches did a pretty good job trying to explain everything, so having more than 1 in mind is good because they may have already answered her question if she only has one. Having said that, S asked pretty much the same question or 2 of every coach that he visited or called him. And they all talked for 10 minutes after he asked the question. They are used to carrying the conversation. Most of these coaches could carry an hour conversation with a lamppost.
If she really likes this school, you might want to try to get a visit in somewhere else first. S kind of surprised me with a couple things he said his first visit. They weren’t awful, but probably didn’t give the best or most accurate reflection on his personality and drive. At a minimum I would talk through some of the questions you expect and how best to answer them. Having said that S told one coach he didn’t know if he could see himself living in the city where the school is located, and he ended up being the #1 recruit for that coach. So some of the blunders can be overcome. The coaches know they are dealing with kids who have never been through the process before, so they may say some things that aren’t really dealbreakers, just a poorly thought through answer by a 15 year old who isn’t used to being interviewed.