Hi IvanC, I'm also interviewing with them next week!
If you are applying to their MATESL, then here is what I went through three years ago. Basically they asked me why TESOL, why degree program, what you wish to accomplish in their program, what's you teaching philosophy (hint: they are student-centered, agianst lectures/grammar focused) I remember it being brief, like less than 20 minutes? Also, they specifically asked me if I was interested in their TAship. My impression was that they were testing my language proficiency (I'm an international applicant ) as a potential TA rather than my qualification for the program. From your previous posts I would say you don't need to worry!
However, if you are meeting with them for PhD, I would appreciate it if you can share some with me after!
Fingers crossed ? for both of us!!!