So the bad new is Logan stole and ate a bunch of grapes. The good news is after an overnight of flushing and two kidney bloodwork panels, he's just fine. What's confusing though, is that since the overnight at the vet he seems to have had a lot of training and manners knocked out of his head. All of a sudden he's exhibiting teething behavior (he didn't show any before), not listening to our commands and showing some tension when we try to insist, like barking, crouching, and staring very hard at us. He much more rebellious. Mouthing again. It's like a night and day change. Is it possible for an overnight at the vets to do this?

Can you remind us of his age? Sounds to me like he went into his bratty teenage phase and an overnight trip to the vets moved that along. I would step up command training and exercise. Limit his freedom, be firm and consistent in his daily life. almost like you are starting from scratch, but it really is just a reminder that he is still a puppy and he needs his manners. If he is 7-8 months old I can assure you of two things, he is a teenager testing you and your boundaries, and secondly he probably is getting his last group of teeth, his back molars, and they for some puppies are really painful to get in. Which makes them testy and bratty, hence the bratty teenage phase.

There are some topics that really bug me and dogs and grapes is one of those topics.  There seems to be no scientific reason for dog to react to grapes - I've looked!!  There are also plenty of stories that a dog ate grapes and had seizures, for example.  Like much of the community, I'm more inclined to think that it's a reaction to some of the chemicals used on the grapes, not the grapes themselves.  

If my math is right, Logan should be about 18 weeks old (you said he was ten weeks old on March 29) or about 4.5 months old.  I'd surmise that the experience at the vet was enough to throw him off kilter.  Were he older, it wouldn't have been so traumatic but at his age - being taken away from home, left at the vet, poked and prodded - he was probably a lot scared and wondering what was going on.  You've been his pack and you left him with these strangers and the last time that happened was when he got taken from his "pack of origin" to come live with you ... he has reason from his experiences in his short life to be upset, no?

My guess is that you're seeing a reaction to his being forcibly restrained at the vet, jabbed and not able to do anything about it, forcibly crated and left alone.  As frustrating as it probably is - hormones and all - just start re-emphasizing his training, what you expect and he'll probably fall back into line.