Animals -- when kept in their right place -- can truly be a blessing. I love them! A favorite article of mine is "Animals: A Gift From God ; Keep a Balanced View; A Pleasure Forever!"
http://www.watchtower.org/library/g/2004/2/22a/article_01.htm. I'll just share what I did to keep my own dogs quiet .... I had been keeping them in the side yard (not right next to the house) at night. They felt isolated &rejected over there, & tho not normally barkers, would become so bored that they'd start barking from sheer boredom (even when no sirens or coyotes were about). I brought one of them in at night, at a time. Trained them to go to sleep when we do. An appropriate-size crate, or even a leash, works well for this -- keeps them from wandering around. I just whisper "NO!" if they start to respond to a coyote or siren, & they stop. (They sleep 8' from my bed.) I wanted to keep the dogs outside, but it just wasn't an option. Our sleep was more important than keeping the dirt down in the house. And we have bonded better, so that I find them easier to train & handle ... . Unfortunately, your problem dogs aren't your own to make decisions about! ... Were you aware of dog-collar training devices that release citronella for unwanted behaviors such as barking? The one I was reading about said : "not for stress-related barking". (Isn't ALL barking stress-related?! Which do they mean?) I wonder if your neighbors would be willing to try something like this? Plus, giving the dogs something to do, as in a toy they really enjoy playing with that's safe to leave with them unsupervised, rotating among several to keep things interesting ... But that will only help if they feel like playing.. My dogs seem to get depressed when isolated away from us, & won't play until near us again. ... Well, that's my 2cents worth.. I can't really recommend or endorse them, as I haven't used them. But, these are examples of what I might have tried next (after consulting a vet & trainer):