knowing a common name is never sufficient to find out for sure if a plant is toxic. ALWAYS be sure to get its scientific name. Int his particlualr case they are both toxic.
The one Eric refers to is in the same family as Rhododendron - Ericaceae (not the same plant) and the Sophora in the pea family (Fabaceae). Both are toxic.
Schefflera and Ficus are commonly used. They each have minor toxicity, but your veield would have to eat an awful lot. If ficus sap get in the eye an infection can occur. You will also find varying claims on different plant sites. A few reliable ones are:
www.ansci.cornell.edu/plants/
lancaster.unl.edu/factsheets/031.htm
www.ces.ncsu.edu/depts/hort/consumer/poison/poison.htm
lancaster.unl.edu/factsheets/031.htm
keep in mind that your cham will spend much of its time in the upper part of its cage basking so you will have an opportunity to see him. If he is deep in the plant he is hunting, cooling off or simply doesn't want to be seen 
see the link below to other cham resources as you get ready for your new guy/gal
lele
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Chameleon Help & Resource Info
1.0 Nosy Be Panther Chameleon - Cyrus
0.1 Veiled Chameleon - Luna. She's now hanging from her big jungle gym in the sky
1.0 Beardie - Darwin
1.1 Side-blotched lizards - swifty and blotcha for now 
0.2 felines - Kyndra and Lita
0.1 African Clawed Frog - Skipper
0.1 Chilean Rose Hair Tarantula - Rosa Leigh Died 4/21/06 
0.1 Goliath Bird-Eater Tarantula - Natasha donated to science 4/4/06
?.? Pinktoe Tarantula - no name yet