Marty was asked to stay on staff by Coach Allen as a bridge to the team, and accepted. It was easy and logical to ask him if he'd like to be head coach when Allen had to step down. It is my understanding that at that time he was named coach for the season - I may be wrong. So, that may or may not be interim. Whether he's there after this year, I couldn't say.
Unfortunately, I can't speak to what the athletic department thinks/feels.
That said, this thread was about Holmes & Dayton. Sorry if it is starting to get hijacked.