Hi, I'm an MS1 here and hopefully I can answer some questions.
First, I know it says business casual for Friday, but everyone (boy and girl) wears a suit anyway. Solidarity? You'll walk a lot so ladies, wear flats unless you have rhino skin on your feet.
I submitted in July and didn't interview until November (post NOV 15 pre-match), and that was IS with a 34 MCAT. Don't lose hope. UTSW not only sends out acceptances on NOV 15th but also 4-5 times after that before the TMDSAS match day. November and December (and even early January) interviewees can still get picked up before match. It can happen fast--I got accepted within two weeks of my interview. And there IS wait-list movement, every year.
Questions vary widely but the most important thing is to stay calm, be your normal awesome self, and demonstrate your interest in medicine. Some kids said they were asked science-y questions. I was, too. It was "what can you tell me about cholesterol metabolism." My answer was "absolutely nothing." It didn't matter--it just meant I got a massive tutorial on cholesterol synthesis during my interview. Just try to be calm and remember that UTSW wants to fill it's class with brilliant, empathetic students who will enjoy every second of medical school. If that's you in a nutshell, you'll be just fine. No need to convince your interviewer that you're already an expert on medical sciences.
Good luck!!!!!