Much to my dismay, my Labs grab people and pull them in, also, with no special training to do so. Labs like to retrieve things out of water, even people.
Sniffing during training can be a sign of stress, like an avoidance behavior. Just Google "dog sniffing sign of stress" and if you want, you can spend at least a week reading about it.
If he went to away dog training, it's likely they used a lot of pressure to train the dogs, which may not have been the right fit for this dog and he is shutting down. Trainers often feel pressure to train a dog to a certain way within a certain time period. Some dogs are pressure sensitive. They are typically handler sensitive as well, and if you are a high pressure handler, which, I can't say for sure but reading your post it sounds like you might be (I am, and I have a handler sensitive dog), if you don't make adjustments in your handling and training style, this is what you'll get.
A handler sensitive dog does not "test". They either don't know what you want or they are stressing out because they are over threshold or freaking out because they are afraid of being wrong and have just lost their brains. So, if you punish him for being less obedient, it'll either make him worse (frantic), or he'll stop doing what he is doing and do nothing, but he'll be shut down and give you that "I'm being punished" look. Many pet owners and pet trainers see a shut down dog as obedient.
Try not to compare him to the other dog. Labs (and all dogs, really) come in a range of temperaments from the hardest dog the softest dog, and must be trained with their unique temperaments in mind. The neediness is a dog that is afraid of making his own choices because it might be wrong. They remind me of that old cartoon where the little dog is (annoyingly) trying to get the bigger dog's approval. A soft dog likes structure, as in routine, and exercise is always good. Consistency is important, meaning that each command is given a specific way every time. If you give the dog a command and he does not comply, first look at how you gave the command. If it was any different than usual, don't blame the dog. Micromanagement turns them off, shuts them down. If the dog was given free reign at one point, sent to a tough trainer, an now has a high-pressure handler (you), this sudden change in the rules could make any sensitive dog somewhat neurotic. If your significant other did not have boundaries before, the sensitivity may not have been recognized.
Training sessions should be short and fun with treats and games. If the dog opts out of something like retrieving, let it go. In fact, if he decides not to retrieve, give him a hug and a pat and tell him it's OK, don't push him. You might find that after doing this awhile, he opts to stay in the game longer as it becomes more fun and less stress. If you pick at him, it'll make things worse. If you don't have competition goals with the dog, I would not worry about precision or the minute details. Don't drill him. Train in a low-pressure way. I taught my dog utility signals easily and without stress while cooking in the kitchen and practicing casually while cutting veggies (and using them as rewards). Training doesn't need to be formal and sensitive dogs learn better with less stress if you teach it informally then gradually become more formal/structured once the dog knows the exercise and has a history of fun/rewards/happy times while doing that exercise. Anything the dog learns in a negative manner (to the dog) will be associated with that negativity unless you re-teach it in a low-pressure, positive way.