Lakota is exhibiting pretty normal puppy behaviour. Some dogs stay in puppyhood longer than others, and I can't speak for all the breeds who do, but I know Labs don't grow out of their puppyhood for about two years. The other dogs do what many dogs do with boisterous puppies about. They warn and they sometimes nip. There is a fine line where their actions go past necessary and into a problem and you'll have to decide where that lies. Big dogs aren't always dominate over smaller ones, and I know our little schnauzer bullied my DD's ridgeback and the nipping at legs and bellies made him nervous. There is also the pecking order and the new kid on the block, unless he challenges the older dogs, will be at the very bottom of it.

My huskies always steal from the other dogs, try to take toys away, take all the toys and just guard them, that kind of thing. Since all my huskies have done that, I consider it normal husky behavior.

Some of the growling is about guarding important resources- the couch, a chewy toy, etc. That may escalate, so watch closely for problems. We had to stop giving my first husky rawhides because he would turn into an evil thing even if he wasn't actually chewing it any more.

They may work out the interpersonal relationships. My Ana doesn't like any dogs near her for the most part, so the others learn to leave her alone quickly. If she initiates play the others will join but otherwise they don't push her.

Try screaming in pain when Lakota bites. That's what another dog would do.

It's all very typical puppy behaviour, and your existing dogs will growl to teach the pup when he has crossed the line by getting close to their food or biting their legs etc and lakota will learn from that.

"Lakota is ADHD we think as he can't seem to focus on one toy at a time."

just about all pups act as if they have adhd :), puppies have a short attention span and they are energetic but you dont want lakota to learn to entertain himself because that often leads to chewing things or digging holes or other problematic behaviour.

Dakota is a baby, and you need to engage with him and keep him occupied, and exercise and games are a great way to get a pup to burn off energy in a positive way, and a more tired lakota will not pester the older dogs so much as well.

I think all he needs is regular walks, throw a ball or toy for him and play with him so he doesnt get bored or have too much pent up energy. My dogs are 2 and 3 years old and they still have energy to burn so I play with them everyday and take them for walks to tire them out. puppies are a lot of work and lakota is just being a pup. He will outgrow some of the biting behaviour as he gets older but pups bite and chew all the time. when my pup bit me on the hands I yelped and it didnt work with her but she did mostly outgrow it and learned to bite more gently instead of painfully.

LOL! I laughed at "When do puppies learn to entertain themselves and stop being ADHD?" My Rocky, even at 2 years old is that way. How funny.

My previous dog, Dakota a husky mix, used to always steal Lily's chewy/toy even when he had his sitting next to him. I'd walk throught he room and he'd be surrounded with toys and Lily would have none. I'd give her some of his. She made a game of running around with one in her mouth and look back at him, since she knew he'd shase her. It was so cute.

I think you needf more time for everyone to settle in, besides all the good info given by other posters.

Is your new puppy getting a ton of exercise outdoors? Puppies are like children. They need more exercise than an adult human can conceive of. A bored puppy is a holy terror while a tired puppy is a very good puppy, as the addage goes. (IMO most human children need a heck of a lot more exercise than they get these days, but that's off topic.)

Take Lakota outside for long walks twice daily or more and if he can also run off leash safely somewhere (in a large fenced area for instance), his pestering of your older dogs should slow down.

Are there any puppy play groups in your area that you can attend with Lakota so that he can play with youngsters his age?

I agree with trancegemini that your older dogs are correctly teaching/communicating to the pup that harassment is not socially acceptable, and I would not interfere. They are being good role models and mentors to the small one. If I intervened at all it would be to prevent a pup from bothering his older housemates, using distraction or gating him in another room for awhile until he settled down. If he doesn't settle down, he probably needs another long walk.

Enjoy the time with your puppy because they don't stay little long, and you'll look back someday and laugh when you remember his puppy antics.