He's a lab so I'm guessing he loves his food?
Get yourself a good treat pouch and make sure it is fully stocked with tasty treats for a walk. I use this:
www.amazon.co.uk/gp/product/B078RMYYCP/ref=ppx_yo_dt_b_asin_title_o02_s00?psc=1&tag=mumsnetforum-21&ie=UTF8
And have a supply of chopped hot dogs in the fridge, ready to go. They are tasty, easy to swallow quickly and stinky. Perfect.
On a walk, if he pulls then stop still, use a piece of hotdog to lure him back by your side, feed him and start walking again. The chances are he will pull again almost instantly. Just repeat. Be prepared for the first dozen walks or so to be slooooow but be consistent. Your dh needs to follow the same routine and never waver.
Pulling on lead = a brake that stops you still
Coming back by your side = a treat plus releasing the brake and you move forward
You'll need to walk him properly while training is going on so, when you're not prepared to train but need to exercise him then try to drive him somewhere you can let him off lead. Alternatively, have 2 clear bits of kit so he can tell the difference.
e.g. a body harness with lead attached = you need to exercise him but do not have the time or patience to train and just accept he will pull
a collar and lead = training time.
For the lunging at other dogs, practice having him sit and stay by your side, using treats to reward him.
You will need to practice this at home first until his sit/stay is solid. Then only practice outdoors when you are a long distance away from the other dog. As he gets better you can slowly decrease your distance to the other dogs but start a long way off and only decrease if he is successful. If he fails at any point you have gone too fast and need to up the distance again. This will mean you will look foolish or rude as you maintain an unnaturally large distance from other dogs but does need to be done.
This is really worth doing because excited lunging can become frustrated lunging can become aggression over enough time and repetition. It needs nipping in the bud now. Don't worry about him getting to 'say hello' to other dogs. He doesn't need to. Right now, he needs to learn manners and keeping his distance is the best way to start this.