If he is comfortable sitting on your hand, try taking him outside in the sun. Just sit there for a bit and let him bask. The natural sunlight seems to get my chameleons system moving.
He may not have wandered too far. Keep looking in plants/trees (sometimes they like to get up high as well), see if your neighbors will let you look in their yards. Depending what birds/animals are around where you live he may have been taken by something.
If you find him, don't leave him...
I agree with the live plant (pothos and schefflera are good options).
Also I would double check what you are using to measure the humidity with and maybe compare it with something else. With a glass cage and fogger going that seems low.
Room temperature water should be fine. It's not like you spray them directly so it shouldn't really affect their body temperature and even if it did they can go back to their basking spot and warm up again.
Your lightning sounds fine as well.
Sounds like he is just trying to adapt to his new home.
The tasting/licking is fine they use it to help explore and see if other chameleons have been there. He is probably still dark after being stressed from the move, this should change after a few days. You may not see them drink much...
Yup, I would start with getting the substrate out and then think about a larger screen cage, but maybe that cage is bigger than it looks in the pics.
I like the look of the plants and stuff though.