Thanks for your replies, we had poor Johnny looked at by a local Chameleon expert (has been caring for, breeding, and raising Chameleons for the past few years now and often rescues injured ones, and has a vet friend that specializes in reptile care).
One of Johnny's main symptoms, which I neglected to post, was a black hole on his tail. This hole was not caused by cricket bites or a burn, but it appeared to be something eating him from the inside out. We now realize the person we bought him from was not a breeder, but an importer/exporter, so it is very possible Johnny had a parasite or bacterial infection.
Unfortunately, Johnny died over night, before our friend could start administering antibiotics. He did not die of dehydration, and we had been misting the environment 3-4 times a day. Whatever hit our Chameleon, the symptoms appeared over a span of 2 days and he was gone quickly
Thank you for all of your support and for responding to my post, I really appreciate it.