Marsye,
Your babies are adorable! After I read your post I googled giving Melatonin to dogs. There's a lot of info out there. Evidently it's used more for stress relief than to get dogs to sleep better. I wish I'd known about it when we had our beloved Keeshond. She was terrified of thunderstorms. We always knew when a storm was coming because about an hour ahead of time she'd start to hide. If it started storming during the night she would wake us up until we'd pet her and hold her to comfort her.
Fireworks were a nightmare for her, poor thing. I would shut all the windows and turn on the a/c (if that wasn't already done), which helped a little, but she was just so scared. We always watched our town's fireworks from our back yard, but eventually I stopped watching them and stayed in the house with her to keep her calm. I should have gotten a sedative from the vet, but never did. From what I read on the internet, Melatonin might have worked well for Keesha.
Marsye, Keesha and Sammy (our Peke), were very loving and close like your dogs. However, for some reason they'd get active at night and start growling, racing back and forth through the house, and playing/nipping at each other. They didn't do it all the time, but fairly often. It didn't last all night though, just for about an hour then they'd collapse and go to sleep. Since your dogs are doing this the entire night, have you considered crating them separately to correct their behavior instead of or in addition to using the Melatonin?
I just love their pic. They really are sweeties.
Sandy