A locust is a species of grasshopper that has a "swarming hormone". When they come into contact with numerous other of their species they become gregarious.
I have a male Oustalet's who free-ranges the back yard 24/7. He goes from 8 ft to practically the ground as he basks, thermoregulates, and "hunts" (I feed him but he does find treats occasionally). To claim that a chameleon will not use their entire enclosure indicates to me that there is...
I concur with Trace, that chameleon is 100% xantholophus. A jack-jack would have a much tealer hue to it as well. The yellow stripe is also much more prominent. In addition to the reddish-brick hue of the horns Trace mentioned.
That middle guy looks like he's missing his tail. Or is that just an illusion. That last one you have pictured is really a neat specimen, you can clearly see gracilis and calyptratus in the head structure.