Also, I assume his teeth have been checked and floated, right? if that has anything to do with this. The avoiding the bit, the pigrooting and even bucking might be part of him disliking bit contact.
I do agree that he has found that he can get away with this, but first check his mouth and then maybe get some help with a trainer for both of you. little things like avoiding the bridle, lead into bigger things.
But the cardinal rule is always to eliminate the possibility of pain being the source of the problem.