Welcome to the board and Buzz is a total cutie. I'm Kat and my pups are listed below in the signature.
Kaila is a mouthy dog. When we are playing she will take my hand or arm into her mouth and just hold onto it. I taught her "no bite" when she was a pup so that she doesn't put any pressure down but I never could really break her of the mouthyness. So we compromised and since she only does this with me, I'm fine with it.
For chewing on stuff that they shouldn't the "leave it" command works great. When Shiner grabs something he shouldn't or start eyeing something I give him tell him leave it and then give him one of his toys. They learn really quickly what's theirs and what's not.