This is my first offseason that I need to hire new Coaches and I have 3 open slots and one is for Head Coach but its telling me I dont have the funds to offer contracts. I looked at some of my coaches and every one of them is over 3 mil, my kickers coach contract is over 4 mil, is this normal? Seems a bit to much for me

Yeah, there were some issues especially with AI teams offering ridiculous contracts that has been tweaked, so the numbers will start coming down. You should still be able to offer minimum deals to guys until those others have their contracts run out.

You can also replace some position coaches with lower contract guys to free up some cash flow - the position coaches have the least impact on your player development (25%)

Is there a way to fire coaches? I tried to promote my Def Coordinator to HC and thought I had cancelled the contract offer for a head coach and now I lost my Def guy. When I look at the coaches and contracts I dont see any options to fire/release the coach

If you replace a coach with another coach you are firing the coach that is in that spot.

If your DC disappeared after FA-1 it's most likely that your he got hired as a head coach on another team; you wouldn't have fired him by making an offer and then retracting it.