At my first interview, I asked about things that weren't readily available on the website/open house. Also, while I was shadowing with my OT, I asked her about things she struggled with as a student and the transition to the workplace. It helped to brainstorm questions.
As far as what I was asked, they had 3 questions that they asked all the applicants both in the individual and group. The questions were related to experiences shadowing.
I don't know what to expect from my next interview but most people that I've talked to always seem to say to know why you want to go into OT, have an idea of what you would like to specialize in, and really relax.