I have to imagine that they would work well. We use the Arm & Hammer small bags for our dog as well because of the great job it does containing the smell. But I haven't used these specifically for the dog.
I haven't used it for my dog, but I don't think so. You have to push the diaper through the top, you can't just drop it in. I don't see why it wouldn't work as far as the smell, but I don't think you are going to want to push a bag of dog poop through the top.
I'm sure it would work just fine. I love this diaper pail because the smell is kept from the room so well. The only time you smell a bit is when pushing a dipar through it or changing the bag. The only problem I think you would have is how you would get the dog poop in the pail because with a diaper you roll it up and push it through.