The formal interview with faculty/students is held at the end of the day from about 1-4 pm (meaning you mostly sit around for 3 hours during that time) and you don't know beforehand if you will be done with your 3 interviews early, or have to stick around until 4 pm. As for the questions, they asked the usual during the interviews, however you have the opportunity to ask a member of the admissions committee any additional questions you may have during your exit interview. Hope this helps! 🙂