HI there and thanks for the question
He sounds like a brilliant dog and i am sure with some training and time we can help things and make walks a little less stressful.
I think we need to take things slow. Pick a neighbourhood that is quiet and where you can start things without too much stress. YOu can start with the gentle leader or the collar whichever you prefer to train him.
As someone approaches get him into the sitting position. If he is relaxed and quiet then make sure to praise him with attention and a few treats. As they approach continue to praise him for good behaviour. If he starts to get nervous then you need to ignore him.....wait until he is showing confidence then praise him. When i say ignore i mean don't look touch or comfort him.
Continue to work on good relaxed behaviour. Start things nice and slow. As he gets better and better behaved you can work towards situations where more of the things that make him nervous are eg parks etc
Take things slow and don't be forced to rush things.
I think it may be a good idea to get a bike at home or a skateboard. We can then use these to help desensitise him to these. Leave them out in the yard where he an sniff and suss them out. This will let him get relaxed and calm around them.
From here you need to start using them. If he gets aggressive you need to tell him off so he knows aggression towards these things is not okay. When he is calm praise him with heaps of attention and encouragement.
Keep up with the good work, and i have to say keeping him on a gentle leader will hav some good benefits
Let me know how things go and if i can help anymore
Todd