I just interviewd there earlier this month, and no you will not be interviewing for a waitlist! They have 7 days that they give out admissions decisions, and they save spots in the class for each day! The remaining days are 2/28, 3/28, and 4/25.
The interview is very much just going through your aplication in detail. They want to get an exact timeline for what you did in college, when you did it, how much time it took, and why.
Good Luck at your interviews!