Hi OP. All credit to you for giving this plenty of thought.
I am a dog walker and spend time with lots of different breeds. In my experience a GR is a good option to have around a young family with two caveats:
- A dog is always a dog and can never be trusted 100%.
- Any dog needs to be shaped and trained to behave appropriately for your circumstances. If you put the work in a GR should usually be easy to train to be a good family dog i.e. basic obedience and manners.
Almost all puppies do have a bitey phase though, and you would need to manage this carefully around your child.
Your post above wrt training is spot on. You should concentrate on teaching your puppy basic manners initially over and above shiny clever stuff e.g. focus more on paws on the floor (ie no jumping up), than rolling over.
All breeds have their plus points and their negatives. Then of course you have the outliers who don't act as you'd expect a particular breed to. But in general the plus points of a GR are that they are biddable, loving, eager to please, fun, good natured, easy to train (because they see food and fuss as worthwhile rewards), easy going and much more even tempered and easy going than a lot of smaller breeds.
Disadvantages include their lust for life which can translate into being over enthusiastic, or worst case scenario downright boisterous. But IMO this is quite easy to train them out of with a consistent approach. I walk several very enthusiastic labs and GR but none of them jump up and all sit in nanoseconds when asked to do so.
They have a reputation for resource guarding but this isn't something I've noticed. Please do read about this though- many of the old fashioned methods of fixing this really can make the problem a whole lot worse and a more modern consistent approach should mean it is never an issue.
I honestly think that a GR's enthusiasm is a much better problem to have and much easier to fix than other less gregarious breeds which are more easily wound up, more likely to snap and less eager to please.
I'd recommend the book 'Easy Squeezy Puppy', also ensure you use a reward based force free trainer and bear in mind that mostly trainers train the owner for an hour a week- the owner then goes home and works on training the puppy, and this works much better if everyone in the house takes the same consistent approach.
Things like not jumping up need to be non negotiable and to achieve this you'll need a consistent approach from all family remembers (and also visitors for a period of time).
Sit is another helpful tool as a dog which is in a sit is by definition still and safe.