Personally, I live in a very dry climate as well, so for my veild, what I did was fit plexiglass in the cage on 3 of the 4 sides as well as for the bottom lip of the reptibreeze. That's just what I did, and it works great, just a little advice.
Sounds like you're doing a pretty good job with your chameleon. The only things I would do differently, are maybe put in a few more branches to really maximize the climbing space for the chameleon. Other than that, I'd feed something other than meal worms, like super worms, crickets or roaches...
For Q2, not all plants are completely safe, but there are tons of very common chameleon safe plants that you can get at really any store that sells plants. I believe that the chameleon forums has a spot where you can see a list of safe plants right under the big "chameleon care" section.
For...
Absolutely true about it not as complicated as some think. As a matter of fact, in most cases, it's easier. You have to clean up little to nothing in the enclosure.
A clean up crew refers to bugs and such in the soil ( like spring tails and isopods), they are not needed, but they will eat any dead plants and fecal matter. They are what makes the cage bioactive.
My Veiled did the same thing a few years ago. It felt super weird, cuz my eye didn't shut in time. It was kind of gross to have a tounge in my eye ball, not sure why he did it.
Having the cage full of fog isn't too much of a problem, other than the risk of a respiratory infection. But just to clarify things, why did you put your Cham in a different cage? I understand that you said that it had mbd, but as far as I'm aware, metabolic bone disease has nothing to do with...