Not sure...
Hi there,
I'm not really sure about the safety of using orchids for a cham, but I know that the plants generally won't tolerate the foot traffic from being climbed on. If you like the look of the flowers, I would suggest a fake plant. However, orchid's leaves are usually thick and rubbery so they wouldn't be a *bad* idea to use on the bottom of the setup if you can confirm that it isn't toxic if ingested.
Hope this helps!
Sarah