Hi,
I wouldn't worry if he only wants mice as long as he is eating multiple at one sitting.
Plenty of us have a "mouser" and they do fine.
As for the sheds some do seem to need a higher humidity than others to shed - you could try lightly misting the substrate ( not the snake ) when you see he is in blue. I generally don't worry if it comes off in bits rather than as a complete shed as long as it comes off.