Per his final contract extension, Matheny will be paid by the Cardinals for 2 1/2 more years. I do not know its terms, but my guess is that if he works elsewhere during that period, the amount St. Louis owes him would be reduced accordingly. At least, if I was them, that is how I would have written it, but then again, extending him through 2020 would not have been my choice, either. But, that is ownership’s commitment and its impact on the team’s financials (and therefore their ability to spend elsewhere) is likely minimal.
I don’t know specifically about the fired coaches, but generally coaches are on one-year deals or two at the most in rare cases.