I have only done Tempra through the Wood-tek Azbak with success...
Seriously though, I am not the airbrush knowledge base like Mike and Chris but Tempra has solid particulates in it and I would wonder how those would go through the brush... could you do it in craft acrylics? (the 88 cents a bottle things at Michaels and hobby Lobby)?
Plus in my limited experience with an airbrush and vast experience as a kid... Tempras dont thin well, they tend to run bad when watered down. unless you have a really potent air source to barely thin them and force it through but I imagine that would pose it's own risks...
this is probably a question for Chis or Mike but I would be wary myself without "higher knowledge"
BTW: your wife is a teacher? Mine is... I am always doing stuff for her class... it's kinda cool actually. My wife teaches bilingual Pre-K. You can imagine the stuff she comes up with for me to do!!! Right now I am trying to figure out how to make a 5 foot monkey for this years talent show... no wood mind you.... ::rolling eyes::