Sometimes, it is just better to leave the breeder out of the loop until you have a diagnosis. I'd like to think they all have the pup's best interest at heart, but some do get defensive, as though you, who love the puppy with your whole heart, did something wrong. Once you have a definitative diagnosis you can just state facts. Dysplasia is dysplasia....i t's not feeding incorrectly, or too much handling or whatever. Truly, on the breeder's side, bad things can happen to the very best breeders, so no one should be blamed. Bad stuff just happens.
Get a good vet to figure out what's going on and just deal with that. I'm so sorry that Dakota's having such a tough time. It's just not fair that puppies should ever suffer!