One thing I can add after reading your last update on Bon's park experiences is that I've seen a lot of dogs react in a poor way to dogs that are still intact.
Usually it's been neutered male dogs meeting up with an intact male dog. They get all puffy and start posturing, almost as if to say even though I don't have those danglies I'm still tough....

I think you need to be aware that many dogs may react to Bon like this and with his hormones raging he won't back down from them. I would stay on top of his obedience training and I wouldn't avoid the park, but I would be extra cautious. Work on getting a really strong recall out of him as well as a nice long attention command. Avoid situations where he might feel territorial.

Best of luck to you, I hope you are able to nip this in the bud.
I also support you in your decision to wait on neutering him, no matter how trying the next few months may be.