The vet brought his wife, an endurance rider, and she said Snickers was exactly what they would look for in an endurance horse and that she would have seriously considered him for herself if she was looking for a horse.
Turns out he didn't have his wolf teeth, just really bad hooks on his teeth that the vet fixed. However, after checking those, his ears, and other things, he said he thinks that the bridling issue is behavioral, then was made worse by the teeth (which makes sense since we were able to at least get the bit in at first), and now we're going to have to overcome it. They're working with him quite a bit and will fix it before I take him, though I'm going to go ahead and send the check. I guess her trainer has been lunging him a lot and then, when he's good and worked, putting the bridle on and taking it off over and over.
It wasn't an "official" PPE, but I trust the lady and have heard really positive things about the breeder and her horses from other breeders and people in our local Arabian world I've talked to. I did a little clicker training with him (I started a couple of months with my colt and it's been fantastic!) and plan on visiting and working with him myself while he's there too, so then we'll get a good feel for each other before I take him home. They've also taken his blanket off so he can fuzz up before then.
Finally, I brought out my English saddle, which is a little more padded than my Western for both of us, to see if it fit him. It seemed to be a pretty good fit and even pressure all the way. Plus, I don't know how well my Western fits him considering I bought it for my QH and Snickers is built quite differently haha. The English is a bit more flexible and seemed to fit to both me and the (old) owner ;)