Hi,
I'm a dog trainer and wanted to respond to your comments about the muzzle. Of course, I can't give you specific recommendations for your dog without having met you both. Muzzles can be quite helpful. However, there are some issues to consider, depending on the type of muzzle you are using. If you're using a nylon muzzle (the kind typically sold at petco, petsmart, etc. - you can see a picture here: http://preview.tinyurl.com/ydth9b), you should not keep it on the dog for longer than 5 minutes at a time. Any longer could cause the dog to suffocate, since they are unable to pant while wearing this type of muzzle. (FYI, they may say they allow panting, but they actually don't.)
Basket muzzles are muzzles that can be kept on longer and are quite safe for dogs. They look more like traditional muzzles, however, so its hard for some of us to get over the fact that we're muzzling our dog when we use these. You can see what they look like here: http://preview.tinyurl.com/ym6298.
Good luck!
Erin