that was an AWESOME show! i agree, that she might see your B/F as the leader and not you. you may also want to try walking her short distances, and doing obedience at home, just so she starts to see you as a leader also. i don't do the muzzle grabbing, but mainly b/c i can't grab around my dogs' (three out of five of them at least) jaws unless i use two hands and it's pretty awkward. the water bottle does help a lot though. we've also had great luck with putting the food bowl down and making ours "wait" until we say "go eat." that way they know i control the food source, and if they act up, it'll just be longer until they get the release. the NILIF (nothing in life is free) might be a thought, though she may be a little young for it now. if she knows basic commands though, you may want to give it a whirl and see how she reacts.
also, you may be aggravating her a little bit with not only changing the amount of food she got, but also the time she ate. i've noticed puppies do great when they're on a schedule, but at the same time if they're super used to it, it can cause them to act out if it's disrupted. consistency really helps. it may be making her a little unsure of things, esp. if you haven't had her long and she had to fight in a big litter for food, or had a bad experience with food availability as a baby.