I wouldn't worry about them climbing. It's far easier for them to just fly out. I believe it's actually safer to feed them only the larvae of the rice flour beetles. Let the beetles breed in a plastic shoebox(es) and feed off larvae to your frogs, the same way you would mealworms. Can't help you on the hoya though...I was under the impression, however, that they were poor candidates for terrariums anyway. Though I never really looked into it.

Alexis, the springtails are a good source of food, excellent in fact. Plus, you don't try to keep them in a food dish. Dump them into the tank and hope that they set up residence there. They are very good for a tank, and the frogs will hunt them and eat them. They break down frog waste, mold, etc. I highly recommend dumping a lot of springtails in the tank and just letting them be. They even break down the waste of my tomato frogs, which one poop of theirs is about the size of one of my whole dart frog's body! So they are really good at cleaning the tank.

I am getting some rice flour beetles in the mail any day now. I know nothing about keeping them. I will have to learn.