I Have/had still have a pygmy chameleon. I will say that they are very FRAGILE and need great care. Unfortunately they seem to die for no apparent reason. Oh a 30x30x30cm exo terra is adequate for 1 pygmy. They are cracking little things I love them but just so hard to keep. Do lots of research and best of luck.
I have a pair in a 90x60x45 glass viv. It is fully bi-active and loaded with plants.
I use air con to keep a stable low temp of 23 and a stat controlled halogen at a basking point of 28. This means that the viv is cool, which is VITAL but they can obtain heat if required. It is the large space that allows this.
They do use the hot zone through the day.
Water is essential, multiple spray downs daily are essential as is a full and varied diet.
They actively take springtails one after that other, then small crickets and even small waxworms and calciworms.
They have a T5 UV source and a jungle dawn system. I see them use the UV during the day.
Every day in the late evening they got to ground and stay there till morning. When the lights come back on they get back in the undergrowth.
Remember, 99% of these will be wild caught still! they are super fragile and need a very gentle worming. Verm-x is best I find being herbal.
Then don't handle them, just let them get on with life and they may reward you with eggs, again females seem to expire after laying even In the wild.
We need to know much more about this group before they can become established and available to the masses.