If you tie the variable part of it to the gross revenue, that's 95% guaranteed. However, unlike the other variable pay concepts, this one has no upper bound.
The same contract executed day one can be worth double or more over time -- and is in theory tied to the performance of the team and the creative genius of the coach (since he can also be a marketing / sales person for the product in addition to the coach).
You are basically telling the new coach:
1) Salary is $4 million paid monthly -- so you have cash rolling in to cover "basic" living expenses
2) You get all the perks listed in the original post -- those don't buy you hotdogs on the street, but they are tangible
3) The gross revenue payment is annual and given ND's track record it is a lock to be worth at minimum $4 million per year.
4) You have the only standing contract that can take you over 10 million in all of college football. Inflation alone is going to add millions to your contract value over time.