You're probably going to hate me after you get done reading this
Honestly, your planned cage sounds
way too small. Vertical height is very important, and panthers are very active chameleons. When I kept them, each animal had its own full-size ficus (not huge, but not a bonsai tree, either) inside a screen cage measuring about 5 ft high, by 4 ft by 3ft. The bottoms were those large under-bed rubbermaid storage containers.
I would also not recommend trying to build a chameleon enclosure into anything with solid sides - it's just not a good idea because there will be ventilation issues.
Also, consider your choice of plants: Chameleons feel the most comfortable when they have good climbing branches, plus a lot of foliage to hide in. Your temp cage has almost no cover at all. Bromeliads will not offer the sort of habitat that your chameleon will need to climb around on, plus these plants will trap water and waste and will quickly be a source of bacteria.
As far as misting and humidity, I covered 3 sides of the cages with plastic during the winter months, and misted by hand. I just prefer that because I can regulate the amount of water and make sure the animals drank. During the summer, they went outside, cages and all, and I just hosed everyone down 3 times a day. That might not be possible, depending on where you live, but the chams liked it.
ETA: I honestly don't know why there's a chameleon section on here. Beyond the small ground-dwelling Rampholeon and Brookesia, I would not consider chameleons to be good animals at all for vivariums. They just aren't suited to vivarium-style enclosures.