My interview ended up being more stressful than I thought it would be, but that was more my fault than theirs. I went into it extremely prepared, which gave me a little too much confidence. I underestimated how nervous I would be. The interviewers themselves were very nice. But I was so nervous for the first question (tell me about yourself), and it just hit me so hard right away. I had to take a moment for take a deep breath in the middle of my answer. But then I was fine, and the rest of the interview went really well. They did ask more "personal" questions (like about my application and stuff) than I expected. So be prepared to answer questions about that. As silly as it may sound since you've spent so much time on it already, read your entire application very carefully a day or so before the interview.
However, I do have a friend who had taken anatomy and she was asked what animal a skull belonged to and what she thinks it ate. I think they were mostly looking for the point at which she would stop BSing and just say she didn't know. Apparently they've also asked questions about history for the same purpose.
But overall, fairly low-stress from what I've read about interviews at other schools.