I think the biggest place to save weight and bulk is if you are using ordinary supermarket dog kibble, such as Purina or Alpo. By switching to a premium food (do the switch very gradually and weeks, maybe months, before any trips to make sure he tolerates the new food), the dog gets the same amount of calories with a lot less bulk/weight. I've seen studies of this--your cost ends up being about the same as the cheaper stuff because you feed much less of it. Best of all, using premium food also results in less residue to clean up at the other end of the dog's digestive system! Talk to your veterinarian about this the next time your dog goes in.
After watching my dog bash his pack into rocks and trees, I don't think I'd want a lighter pack for him. You can teach a kid to take care of a silnylon or dyneema pack, but a dog is another story!
I use a quart yogurt container for food and water. Far easier to keep clean than one of those nylon gizmos, as well as lighter and cheaper. My dog doesn't like to catch frisbees (he has an overbite) so no dual use as in your case!
There are lighter weight tie-outs and you might want to investigate in your pet store. It of course depends on how much stress your dog puts on them or whether he chews it! That being said, I never go off and leave my dog tied. Not only would he annoy everyone in the neighborhood with barking and whining, but he'd be too vulnerable to predators! If I leave camp, he goes with me on leash.
The dog in the picture wouldn't need a pad or a jacket; (s)he would fit nicely into the bottom of a human sleeping bag as a foot-warmer!