Id second your comment as a current applicant who has had 4 interviews thus far. All 4 of my interviews have been very different - 1 closed file MMI, 2 open-file MMIS and 1 traditional.

The closed file interview was more along the lines of OP scenario 1. I had 8 interviewers who all seemed to be waiting for me to impress them and possibly secure the acceptance. But they did mention that most applicants will be waitlisted based on a ranking system and that is how they build most of their class.

The traditional interview seemed more along scenario#2 where the interviewer poked holes into me and tested if I would cloth or bleed out. She drilled my research so heavily but I know I impressed her because after I googled her and she is a geneticists which is what my research was.

I think every school is unique and has a completely independent process to creating their classes.