Not legal advice, dog advice. I think you need to start thinking of your dogs as dangerous when it comes to confining them. It's pretty likely, given the relative sizes of your dogs vs. a Pom and the fact that huskies have high prey drive, that they were going after him like they'd go after a rabbit or something. Even if they did see him as another dog, two probably somewhat nervous and over-excited dogs running loose and feeding off of each others' energy are often going to act differently than two relaxed dogs visiting a familiar dog park with their owner.

But now you know that when they get out, they run the risk of killing your neighbors' pets. That also runs a high risk of leading to a human bite, as many bites aren't the result of a dog intentionally going after a person but rather an accidental bite while a person tries to break up a dog fight. But you don't want your loose dog that just attacked another dog to get that kind of bite, either.

"Dangerous" in this context doesn't necessarily mean bad. I have a dog that is seriously dog aggressive. He tolerates my other pets but he'd just as soon kill a strange dog as look at it. He's also literally saved human lives. But you better believe that I've got like 3 layers of confinement around him every time I leave him alone so that if I forget to close a door or gate, he's still safely confined.

In most places, the worst you're looking at is probably a fine and a civil suit, maybe a quarantine (usually 10 days if your dogs are UTD on their shots and you can usually do it at home). But if this becomes a pattern, in a lot of places repeated attacks on other dogs can lead to your dogs being classified as dangerous dogs and/or euthanized. There's likely going to be an official record of this attack so you need to really 100% make sure there's no chance for this to happen again.