All are logical candidates except Fickell. If I were him, I wouldn't touch this job right now. He can do much better.
Freeze make sense from a coaching and location standpoint (started his coaching career at a high school in Memphis), but I'm not sure a program dealing with NCAA violations can go that route.
If I were Tennessee's AD, I would go after Malzahn. Good success at Auburn, including 3 wins vs. Saban.
The problem with Malzahn is they just hired Kevin Steele at $800k a year, and he and Malzahn do not particularly care for each other. To get rid of Steele, Tennessee would have to eat the full $800k from what I heard today. I have to think they hired Steele with the idea that he will become the HC.