Okay, as someone who got a golden retriever pup in August last year after copious amounts of research and pondering, I can give you my experience of what it actually was like:
"I have researched the breed and the initial stages."
Please also research the 7-8 month 'play biting and play attacking' stage that I found nothing about in books etc. Honestly, he went bonkers and thought he was being hilarious running at us and attacking us and leaving me with massive bruises on my arms and ripped clothes. It's a thing with labs and golden retrievers, apparently - they always grow out of it, but I'd be very worried about having a little person around at that stage.
"He is also in a position (once pup is ready) to take him/her into work, not everyday but certainly a couple of days a week."
What job does your DH do? I'm just reaching the stage where I don't have to keep an eye on dog (now 11 months) every moment he's awake to ensure he's not up to anything naughty. I hope your DH realises this. 
"My son is 7 and would just love it I know he will. "
My kids are older and said exactly the same, even signing a "puppy pledge" promising they would always help. They did at first, but after a few weeks, the novelty completely wore off. They got really fed up of the hard work, the boring 'keeping an eye on him' all the time phase. They stopped enjoying him, they actually stopped liking him for a while as he was a total pain in the arse most of the time. 
I disagree with those saying you'll have two babies and then two toddlers. You'll have a toddler dog from day one (straight into potty training) and a baby. Then you'll have a teenage arsehole dog and a toddler. 
" I plan to give pup run of kitchen / dining / family room (wipe clean floors!) " - what could possibly go wrong? But yes, do get a crate, it will keep you sane.
You will probably be getting the puppy blues at some stage - make sure you come on MN to get you through it.
The good news is, my boy is brilliant now. But your first year, possibly more, will be a stressful nightmare - do you really want that AND a wee baby to look after?
Think long and hard OP. I'd wait a bit if I were you - then get a grown up rescue dog. 