Current D1 here! Slacking off on studying for finals, thought I'd check on this year's application thread and see if I can answer any questions...
1) Post-interview white coat size selection: it's unisex sizing, so size down if you're female. They're super big. For reference, I'm usually a size S and even the XS fit like an M/L.
2) Prepping for the MMI portion of the interview: google MMI example questions, type out a response, practice reading your response out loud so that it sounds natural (not like you're reading off a script). Record yourself saying your response, play it back, make adjustments to your response, repeat.
General "formula" for MMI responses: state your opinion/stance (take a firm one-sided stance, don't go down the middle and be ambiguous about which side you're taking) --> justification/reasoning based on ethical/professional/etc. principles --> consider the other side (now is your chance to say why the other side might also be good), pros and cons --> briefly summarize
3) Prepping for PBL portion of the interview: nothing really lol. It's super chill. Just speak when you have something to say (discussion format, don't raise your hand). Pro tip: lean into the camera slightly to indicate you have something to say, this helps avoid awkward moments of talking over people. General rule of thumb: have 3-4 people talk before each time you say something. You don't want to come off as dominant, but you also want to make contributions - whether it's saying a novel idea, making sure the group is staying on track ("have we covered all the facts?," "I think we can say a few more things about this part before moving onto the next," etc.), or fostering a positive group dynamic ("good point," "that's a really good observation," etc.).
4) Application status after interviewing: your status will automatically change to "Waitlisted." I wasn't actually waitlisted, so I don't know if they send you an email to confirm a waitlist position (they probably do).
Happy to answer any other questions. Good luck!