There is no way that Mike Brown fires Zac Taylor. This is for two reasons. First of all, Mike Brown won't pay people to not work for him. He's actually said this. Also, he is loyal to a fault. Remember, he kept Marvin Lewis for 15 YEARS and Taylor took them to a Superbowl. Zac Taylor is HC in Cincinnati until either Mike Brown dies or he quits.
He's not cheap. He's relatively poor for an NFL owner. He doesn't have the cash to pay signing bonuses.