my neighborhood for some reason is full of people who don't believe in fenced yards or leashes dogs
Willing to bet there is a lack of vaccinations too!
Yikes. Take the baby home and work on exposing to anything and everything in your own house and yard. You can set up obstacle courses and walk past in the yard, you can have people come in and walk around or bike or skateboard around the pup, you can have different surfaces, mini agility where the baby walks on a board or over a tiny little A-frame or through a tube/tunnel, you can expose to instruments, music, drums, dropping things, swinging things like a towel around. SO many things to do to build confidence on and off leash in a safe controlled environment before hitting the pavement. I wouldn't walk a dog in a neighborhood with loose dogs. I would NOT take a fearful dog to a dog park because the other dogs will just pick on your dog and make it worse.
So far, you have exposed your dog to who knows what (parvo, distemper, kennel cough), scared your dog with other dogs, and scared your dog with people, bicycles, etc.
I have a fearful dog. Trust me. Stay home and stay put until vaccinated, create lots of successful activites to build confidence at home, have kind people come visit, have a fully vaccinated healthy and friendly dog come play, after vaccinations, get into obedience class and maybe a very light agility 1 class. Do all these things very calmly and controlled. Then make small quiet outtings. Up the exposure only after the level of stress has gone down from the previous things exposed to. Like ripples in a pond, start small and expose slowly and carefully to more and more as the dog can handle it. If you keep doing what you are doing, I am willing to bet you will have a dog reactive on leash to people and animals, cowering at noises, and really hard to do anything with. That is, IF you manage to avoid all the germs.
You can turn this around NOW or keep making things worse. I have one. I didn't do it right. I have since learned. My dog is a homebody. I had to get another dog to go do things with and leave my boy home and happy in his controlled safe world.