Brie is a Pyrenean Mountain Dog @VanGoSunflowers , so as you can imagine, everything is on a larger scale with her. She's been a fairly easy pup, and I'm pretty laid back about it all by now because I've lived with this breed for so long. We're older though (60 ish), with no young children, so the size is not an issue for us. I can appreciate that with a 7 year old in the house, your pup needs to learn good manners very quickly. Teething will be extra challenging for you - the landshark phase is not fun, and long sleeves will become the norm. We were at this point exactly one year ago!
Shouldn't say this, but Brie is still a swine for jumping up (paws on my shoulders these days😬). We use "off" command or a sharp "no!" for jumping, because if you want to teach down/stay later on, saying down confuses the issue, but that's just my take, others might advise differently. I'm not the training guru here, that would be the lovely brushingboots. My role here is housing the resident guard dog (and talking too much....) Yes, "leave it" is vital, it is now my catchphrase on our walks 🙄very often in relation to rabbit poo 😝
I think you've been wise to heed the advice regarding breed. A GSD would probably be okay (even as a first dog) if your child was a teen, but 7 is young to be around such a powerful, strong-willed breed. You may well become addicted to Labradors anyway, they do seem to generate incredible breed loyalty.
It sounds as if you're really putting a lot of effort in, and it will definitely pay off later. I hope your son is okay after getting a scratch, but I'm sure pup will be his very best pal before too long.
If you're sticking around here, which I hope you will, please share pics, we always love to see progress photos.