Hello! First time posting so sorry if the format is off lol. For interviews with faculty of interest, I've been reading some of their most recent publications and trying to get a better picture of their methods and future research directions. I think preparing a couple of potential research questions based on their pubs would be helpful. However, I think it depends on how long your interview with the faculty of interest will be. If the interview is a bit lengthier, I would prepare more questions or think of potential follow-up experiments or anything else that shows that you are familiar with their literature and are able to discuss their project with them. Hope this helps!