I hope you are able to get some good advice for Rita, does she get along well with Sadie?

Not trying to butt in, but I'd also like some help sort of in the same way with Nebo. He does not lunge, growl, bark, etc. at other dogs while we're on a walk. In fact most times he either ignores them or wags his tail and whines like he wants to play with them. He can be in a crowd of hundreds of dogs and be just fine with them all around him...but when they get in his personal space he gets pissy. Not with all dogs, but a lot of them. Yesterday I was walking him and a guy came up with his lab to let them sniff (they had been looking at eachother wagging tails like they wanted to play) I warned the guy that Nebo isn't always nice but he did it anyway. They sniffed for a bit and were real close together, and Nebo (possibly the other dog too) got rather stiff then Nebo growled/sort of snapped at the other dog. He didn't actually bite the other dog, he's never really injured another dog, but it looks bad. Help?