He's had it since he was brought home. *note: that is not a picture of my plant, but one similar* I got the information of the plant to get from the breeder herself. I will call and ask her tomorrow to make sure again. Thanks guys.
I don't believe benjamina is toxic, however it does contain a possible irritant. The white substance that comes from breaking a branch can cause problems if it gets into a chameleon's eye. Many people use this plant species without problems, but there is a risk. Logically this risk would increase for frequent plant eaters.
Ficus isn't considered toxic. I believe the concern with it is in the milky sap that it leaks when the branches are broken or cut. Some feel that it can cause skin and eye irritation.
On the water bowl... the reason that Will expressed concern is because standing water also has a tendancy to grow lots of bacteria. It isn't a bad thing that your cham will drink from it, but you should clean it every day to keep bacteria growth down. A chameleon with a bacterial infection isn't a fun experience. It takes months of force feeding, antibiotics, and luck to get them well again.
Ficus contains calcium oxalate crystals which when ingested (or gotten into the eyes) can cause irritation and organ damage. However, this is a defense meant to protect against insects and presumabley doesn't affect chameleons too severely because of the size difference. Still, if I was the one with a plant eating cham, I'd prefer to err on the side of caution and replace the ficus with something a bit safer and more desireable like Hibiscus.