I REALLY think you should find your local Obedience club (a real OB club, not just random classes) and ask for a reputable behaviorist reference. Even if it is an inconveniece, it'd be a much bigger inconvenience to have a dog that is hyper-reactive with kids and you having no idea why or what to do about it. Not to mention the bad reputation you will be getting from neighbors. A good behaviorist is absolutely worth the $100+ you will spend, so much different from any OB class.

Relatives of mine have a nordic breed mix that they rescued as a puppy - he definitely looks part Akita (super long legs and a curly tail). He is extremely loud and barky when he sees anyone, especially kids, and he's on-leash. However, he has never shown aggression and as scary as the barking seems at first, it's just indicating that he's excited. When he gets to meet any kid, he'll happily allow them to jump all over him. I don't recommend you do this with your boy without the guidance of a professional behaviorist, but I hope this is the case with Zero