"As for the building manager, he's technically sitting on a public sidewalk so they can't do anything, I'm told."
Not even if he's bothering you? I understand you say he's a "nice enough man," but after reading the rest of your post...I don't know about that. Just give him a quick nod of acknowledgement when you exit your building if he's not bothering you. If your dog is small enough, carry him. If not, keep a strong hold on the leash. You don't owe this man an explanation as to why he cannot pet your dog. If he starts harassing you, call the cops.
"We like to snark around here. Sometimes we actually talk about theater...but we try not to let that get in our way." - dramamama611