I think both may be reactions to being taken away from momma, and or littermates too early. The kitten never has a chance to engage in rough behavior and play fighting with littermates. I have a feral that is now almost 14 yrs. old, but I got him at 3 wks. old, and he sucks my shirt as a calming measure. He also has favorite toys that he carries around with him, and he makes a "calling" type of noise while it is in his mouth. Very loud noises, I might add....I agree with the other members advice to NEVER, EVER hit a cat with your hand, or anything else. Also distraction with an interactive toy is a good redirecting bad behavior option. If the cat is not encouraged to play with hands, they usually can successfully be delt with untill they grow out of it.....