Well i emailed the chief pilot and according to him theres a "short question and answer session" Followed by a written test (im guessing just study gleim stuff)? He also mentioned the questions will be at your certificate level or below and that some questions will be relative to imparting knowledge to students that don't share your level of expertise. However i don't know if he was referring to the question and answer session or the written test itself.
I also saw one of you guys mentioned bringing books and lesson plans? Is that normal to do for a CFI interview? Would be nice to have my CFI binder with me.