If a decision is made after the season that it is time to move on - which imo would require a losing record, Johnson's buyout would be $4MM. $1MM for each of the 4 remaining years on his contract.
Hewitt's 900K/yr buyout finally comes off the books next spring so if the decision is made to make a move you simply move the money you are assigning to Hewitt to Johnson and you really haven't affected your finances at all.
Most of the names mentioned here imo would be hired at a rate far below what Johnson is currently making (at least 0.5MM). You could take the HC savings and put that into assts and recruiting staff.
Here's the full salary for some of the ACC HC's.
Dabo, Clem $8.5MM
Taggart, FSU $5.0MM
Richt, Miami $4.1MM+
Petrino, L'ville $3.9MM
Mendnehall, UVA $3.4MM
Fuente, VT $3.3MM
Johnson, GT $3.0MM
Cutcliffe, Duke $2.6MM
Addazio, BC $2.4MM
Babers, Syr $2.4MM
Fedora, UNC $2.3MM
Doreen, NCSU $2.2MM
Clawson, Wake $1.8MM
Narduzzi, Pitt $1.8MM
My expectation is that unless a move was made to hire a big name, we would end up in the $2.2-2.5MM range.