If Ole Miss is serious about him ever suiting up again in college, they only have one play. That would be to cop to something small (like less than $1500 in benefits) and propose something like a 4 game suspension. Then they disassociate some booster, cut some official visits, and make the the official proposal to the NCAA in order to expedite the closure of the investigation. A two game suspension would be way too transparent to the NCAA and not really a punishment at all. Besides, Tunsil really won't make a difference for them against Bama but could very well be a huge factor against LSU, A&M, etc.
The other alternative is to do nothing, and watch the NCAA drag this out all season. By doing the above they at least appear proactive.