I'm very glad Winston had a good visit to the vet the second time around!! I think it's important to have good experiences at the vet, so the puppy isn't adverse to going in - the less stress, the better the checkups will go for everyone. And, for some (i.e. filas), that means not spending time in the waiting room.
If I had to guess, I'd say with a puppy and a 5-yr old in the house, there may be a lot of excitement, running, screaming and barking going on... potentially... at times...
I'd want to make sure the whole family has some good down-time together, so they learn to relax around each other.
In our house (no kids, so take this for what it's worth...), over-excitement gets sent OUTSIDE. Inside is for relaxing and unwinding. Outside is for playtime and running around like a crazy-dog.
We used the "yipe" method for bite-inhibition, and it worked very well with all our dogs. That and re-directing to appropriate chew toys. Denna has a very soft mouth (she's 15 months old), and rarely puts her mouth on me... when she does, a little yipe still gets her attention and she backs off immediately.
And, I know I'm going to step in it, but here it goes...
I've also never had a dog react badly to shots at the vet... I guess we've been lucky, too! Denna had a treat in front of her nose when the microchip went in. She didn't even flinch. But, based on her "boo-boo" (elaborated in a separate thread), she has a
very high tolerance for pain... I would expect a puppy to 'yipe' at a shot (or an uncomfortable lift) and reach around with a mouth to make it stop, versus 'growl' - but they might sound similar at the time, depending on who's doing the interpretation.