However, let me ask you this: If switching out the plant for one on the "safe" list (not created by anyone on this board) saves your chameleon's life, isn't that good? And, isn't that a rather inexpensive, non-intrusive thing to try? It's not like anyone is suggesting buying new cages, lights and a misting system.
You have a chameleon that is having issues. You have a plant that may be a problem. Why cling to the plant? Change it out for something on the safe list and see what happens.
It's a no lose situation for you and might well save your chameleon.