A few thoughts for perspective (based on experience, not insider info):
1) The contract is likely min of $40M ($8m X 5 yrs), plus buyouts and incentives, commitments of resources, staff, decision making autonomy, etc. yet serious negotiations began only yesterday. They are moving at breakneck speed if it's done before Monday.
2) The Manny situation may be about a plan B, but it's also certainly about his buyout. I'm sure the admin would negotiate a release if Diaz will walk away from some or all of his severance, but unlike Mark Richt, Manny wants to get paid. It's logical to leave him in place until the ink dries on Mario.
3) The AD situation seems muddied by timing and authority of decision making on Mario. Not surprising the lead AD candidate would want to know who the head coach is before committing, if it's clear the BOD will make that determination, not him. I suspect the "football czar" is another complexity that slows progress. I wouldn't expect anyone good to take the position until those key positions and his ability to change them, are determined.