MarnaLou,

I would be worried about the muzzle because if he growls to attack another dog, the other dog could attack him and he would be defenseless. I think I would not take him until the other issues were worked out. I did use a muzzle for a while for my Cairn, Rosie (RIP) because she had a penchant for ankle biting, but, she was on leash. I then switched to a Halti, which is a collar device that goes over the dog's snout like a horse bridle.

If Stewart was playing in the park with a muzzle on, would he play with it on or relate it negatively? It might make his situation worse.

Just my 2 cents worth. Z(I edited this post)