The hook is caused when the club face is looking to the left of the direction you are swinging
There are two parts to the release, one is the arms turning over and the other is the body turning, we need both of these to release correctly but most of us tend to over emphasize one of them
Reverse pivot means that your pivot is going in the reverse direction that you want it to, when you turn back to the right your weight should follow you and the same applies to the through swing, this is usally the result of a poorly balanced set up