So with the kid he started barking and standing his ground. What triggers him is other people and dogs, i think the people he has gotten better at. He hasnt really reacted as bad as he does to dogs.
I know dogs dont need other dogs. When i got Tucker, i got him from a friend who was in a situation and they needed to rehome him. I took him in knowing i was going to start Agility and hunting with him. He immediately became attached to me, and started to freak out when i left. So we worked with a trainer so he could see its ok if i left the room. But im still his favorite person. Denver taught Tucker quickly who was boss. There was no biting but she growled once. He did start trying to bit her. And i had made another post, a lot of those tips worked and quickly stopped it
I remember your other post. Your dogs remind me of mine, except that my younger dog is a shepherd mix. My older one is Golden, in breed and temperament, like yours. The younger one is sweet, but can be reactive to dogs.
Here are some things I would try. When walking with Tucker, my goal would be to stop his reaction as soon as you can. Your tools could be ecollar, prong collar, jerk on a leash, pet corrector spray, food, moving in the opposite direction, asking to look at you... You would need to experiment to see what works for you. If you have to go all the way to ecollar don't worry that you will have to stay with it forever. You just need to reset him quickly to snap him out of that state. Progress from less to more challenging situations.
Going to classes is great. Seek for a place that is accepting of aversive tools. If he really turns out to be a reactive dog, you will be stressed in a class. If the tools you are using to manage his reactivity are not acceptable it is just not going to work. You will have to give up on the class.
Spend a lot of time playing with your dog outdoors and mix it with obedience. Pick one toy, entice him, be very engaging. Think of this as an exercise for you. If you don't sweat, it is not right. While playing, teach him commands like "heel", "stay", "leave it", and "place" such as sitting between your legs. Start in your yard and progress to fields where there might be other dogs. Be a team. Teach him that you are his universe.
Get a good recall. Again, if you need to go with ecollar to get the confidence, go with it.
Find him dog friends with whom he can play with. You want him to know that other dogs are OK. Goldens are social and it is not typical for them to be suspicious of other dogs and humans. If you don't expose a Golden much to other dogs it is not normally going to be a problem. For other breeds, that can be a problem, unless you live in a solitude. So if you think that his issue is that he is not comfortable with other dogs, do find him some dog friends.
Try to understand what triggers him. Once you understand what it is, it will be easier to correct him. For mine, walking on a leash is mostly fine now. He still have an issue with some of his dog friends, if they come too close to one of us (humans or his dog brother). He sometimes try protecting even people who are not in our family, by defending them with his body and barking and lunging at a dog. The dog could be just fooling around. He can't always read well. So, what I do is I tell a firm "no." But that has to be done at the right moment with a person and dog I trust. He is much slower than Golden to understand what "no" means. It depends on a dog how long it will take to finally get it that something is not acceptable. You will see it in their eyes when they finally start to get it.
Sometimes a dog will be reactive because they are overly excited to meet another dog. So it is really not that they are uncomfortable with the other dog. That behavior is unacceptable too and should not be rewarded by greeting the other dog.
If you are going to use ecollar, I would try to learn about different ways ecollar can be used. In hunting community, a dog is collar-conditoned to understand what he should do when corrected and for Goldens usually this would be on a low level. So, that could work well for recalls and sits. With some behavioral issues, there are trainers who will recommend a high level so that the dog just snaps out of it and say "I am not going to do that ever again. This is bed for me". One can use it in both ways, but the order matters. Try to learn as much as you can. Always trust your instincts. It is your dog.
I hope your problem doesn't escalate and that Tucker and you smooth-sail through his puberty.