Offhand, I don't see what is so difficult about eliminating Turner from consideration...his brief 15-22 record as a Head Coach of a MAC Team (Buffalo, no less) shows me that he does not possess enough experience nor has he proven himself capable of stepping-up to handle Auburn's top spot. If I were a Kentucky or a Vanderbilt, it may be worth the gamble...but Auburn expects a lot more from their football program, and there is not much time for on-the-job training.
Over the years, there have been a number of really good coaches who stepped-up from the MAC and into a big time football program. Heck, Bo Shembechler came to Michigan after being the Head Coach at the University of Miami (Ohio), but he brought with him a 40-17-3 record and six successful seasons before being given an interview.
I don't see why Chizik or Turner would ever be considered for this position. I would just as soon assign an "Interim Head Coach" than I would select the guy, or gal, based on his qualification of sucking less. Would you hire Turner if you were the Auburn AD?