Hey TKO,
I did complete my interview and have also received an admission offer from the University. With respect to my experience it was quite pleasant. My interview was conducted by Prof David who is the director of the program. The major questions asked were with respect tot the topics in your transcript that can be transferrable for the Financial mathematics program. For me it revolved around Probability, Statistics and extremely basic questions about PDE. He also asked me about my motivation to pursue the course in Financial mathematics and the steps I took to change from an Engineering background to that in Finance. Finally there were a few questions about my skills which were more of self assessing my technical skills that were mentioned in my resume. I had the chance to ask a few questions to the interviewer and then it ended.
Just yesterday I had attended a meet and greet with prospective students and alumni. I hope you have a great experience and I'm wishing you all the best.
TLDR : Be thorough with the basics of the concepts in your transcript. You can choose a topic that you're familiar with to be interviewed on. Try to communicate confidently and make sure that you accept your mistakes when you make one and show that you're ready to learn.
Sincerely,
Sashank