The liquid tempera paint is not waterproof because it is a water base paint.
Tempera won't stick to gold leaf. It will crack off as it dries out.
water
no
no tempera is a water based washable paint
yes
To make face paint out of tempera paint, you mix flour and water in a small pain on the stove until it is of the right consistency. After you remove the mixture from the heat, separate it into several bowls and add tempera paint to each bowl until you get the shade that you want.
tempera paint.
water
I suppose if you were doing a faux fresco you could use tempera paint, but this wouldn't be done using plaster but on paper in the same style. On plaster I don't think the tempera would work.
Paint
It may stick to styrofoam because dish soap mixed with tempera paint it sticks to glass.