I just thought id add my own lab experience here.
Jett belongs to my mother and father in law, he was raised with proper socialization,and a private trainer.
He had acreage and was exercised well for the first few years, once my sister in law moved out of home that all stopped then 2 years ago my in laws moved into a residential property and have never ever walked Jett.
I walk that dog every day as well as my own 7 dogs, it is hectic but Jett needs it as he was grossly overweight from lack of walks.
From the day they got him he tore up everything in sight, dug many holes and was so boisterous, this has never been any different even at 3 years old at which point he was still being exercised and trained.
He is now 9 years old and the most boisterous older dog i know, he is great with my 5 year old daughter but regularly knocks her down from excitement, he is also very friendly with other dogs but plays to the point that most dogs get sick of him, i have only ever met one american stafford that could keep up and tolerate him.
To put it simply if you get the wrong lab they can be troublesome, i will admit that Jett has not had dedication and love in the last few years but even in the 3 years he did have it he never ever calmed down.
Even with walks and love from me he is an incredibly sad boy who barks excessively from boredom and pulls backwards when the walk is over and i am putting him back in his yard.
I have found Labs to be a tougher breed and i rescue dogs so at the moment have a cocker spaniel, bull mastiff x great dane, bull terrier x, kelpie x,greyhound x,maltese x and a pomeranian and quite honestly my point of view of labs is strange, i try to look at them without judgement but Jett is the only one i know well and he is so much work.
I understand there are many labs that are great but this is just my experience.
I would happily advise an older dog be it from a registered breeder or rescue, lab rescue in NSW are great.
One of the most in a sense easier/smaller and child friendly breeds i find(in rescue anyway) are a maltese.
Yet again to be sure of a calm temperament i would go for an older dog, a totally different breed may suit you if it has the right personality and exercise needs.