So I have been occasionally following this discussion thread and wanted to offer my input/insight. I am currently a 2nd-year student in Mount Marty's CRNA program and am in my clinical rotations. While I don't remember much about the interview questions, I felt the interview was more of a get to know you as a person type of interview. I agree with some of what others have posted - be true to who you are, admit when you don't know something, and answer honestly (even if you are worried about how it makes you look). I do remember being asked about a clinical mistake and what I did/what I learned from it, but other than that, I don't recall many clinical questions. I did not bring a support person with me and it obviously did not affect my admission or my interview. Also, take advantage of the current students that will be at the interviews - ask them questions, opinions, etc., they are a great resource for information!
Regarding clinical sites - I chose mine based on what type of experience I would be getting. I wanted a bigger city with more of a variety of cases but didn't know much about which states utilize what practice models. Sioux Falls is a supervisory model, while some hospitals in Omaha/Council Bluffs are independent practice. I would suggest looking at the AANA website or other sources to see what practice models are utilized in what states as that could influence your experiences.
Good luck with the interviews!