You said..."What is the best way to line the bottom to catch water/dust etc? Should I put something inside the cage or place the whole set-up inside a tray?"...the important thing is not to let water sit in the bottom or in a tray. You don't want bacteria or mold to build up and cause problems for the chameleon.
You said..."What is the best way to secure the lamps outside the mesh? I'm hesitant to put the hoods directly on the mesh (in case of melting? is this even possible?)...some people raise them on things that look like tomato cages. Others suspend them from the ceiling above. Appropriate basking temperature is important for good digestion.
You said..."Should the lights be on the top or sides?"...I always keep them on the top.
You said..."I live in a very dry climate. Is a fogger a good idea to keep up humidity/provide drinking water?"...I've never used a fogger...sorry I can't give you an answer.
You said...."How often should I be dusting with calcium?...since most feeder insects have a poor ratio of calcium to phosphorous, I dust at most feedings with a phos.-free calcium powder.
You said..."Multi-vitamins?"...I dust twice a month with a vitamin powder with a beta carotene source of vitamin A. Beta carotene sources of vitamin A can't build up in the system like preformed vitamin A can. Excess preformed can prevent the D3 from doing its job and lead to MBD. There is controversy over whether all chameleons can convert beta carotene so some people give a little preformed once in a while.
I also dust twice a month lightly with a phos.-free calcium/D3 powder. Exposure to UVB from tube (compacts are not recommended) lights or the sunlight allows the chameleon to produce vitamin D3 which allows the chameleon to use the calcium. D3 from supplements can build up in the system though so don't overdo it. The UVB should not pass through glass or plastic whether it comes from the tube lights or the sun.
D3, vitamin A, calcium and phos. are the main players in bone health (and other things)and they need to be in balance. You need to look at the supplements, what you feed the insects and what you feed the chameleon.
You said..."How often should he shed?"...depends on the rate of growth. I usually don't grow mine very fast.
Gutloading and watering are both important too.
