Wow. I think if I saw a neighbor doing something like that to She-Ra's collar the police wouldn't really have to worry about taking my dog into custody. Screw with me, screw with my family…but don't touch my dog.
That said, don't go looking for revenge on these people, but be vigilant. If he's brazen enough to come on your property and mess with your dog, he's probably got no problem doing something a lot worse. I believe in karma, but sometimes karma needs a little help, too. That said, god help his cat if it ended up on my side of the fence, so to speak.
And there's something just fundamentally wrong with someone who doesn't appreciate a good baroo, anyhow.
I'm really sorry for what's happening to you right now, but moreso for poor Jack. Just try and concentrate on how much fun it will be when the two of you are reunited on (hopefully before) the 26th.