Change from the choker to the prong collar, use a back up collar attaching to the main collar with a tab or there are leashes designed for this purpose. With his lunging, he can easily damage his trachea.
As others have said, work with him under threshold. Fence with dogs is a good idea, BUT if he reacts walking on same side of road, move to the other side of the road and walk. Saying repetitive can be any number of walking back and forth. You want to keep it to a short time/number of walks back and forth; stop before the dog's tension builds to a high level and he reacts. If he reacts, move away from the area, let him settle, once settled, come back and make one more successful round and call it a day.
The same idea applies for the other areas you work with him. Find the distance he doesn't react and start there.
For the toy as a distraction. Some dogs become more amped up when using a toy, how does he do when using food as a distraction? Not the kibble, but the really yucky stuff dogs go nuts over.
Especially with a reactive dog, having an experienced trainer involved is seriously worth the cost. They can see things we don't or we miss. With their eyes on the dog and his behavior, they can employ any number of training techniques tailored to what your dog needs.