Re: Paludarium Build
Species in the genus Bombina produce a mild toxin, that can build up in a water supply and affect other amphibians in a negative way(due to their extremely porous skin). Although it may not be too detrimental through simple contact between the animals themselves, it can and will build up in a small closed system like a terrarium/paludarium, and compromise the health of any other amphibian you stick in there with them.
So my question to you is, do you think its right to forcibly keep two species together in a small glass box, that would normally have no interaction ? Especially keeping in mind the fact that to one of the species of frog the only water supply is covered in a film of toxins?
Besides that, like someone else here said, the bombina would enjoy the space much for than the treefrogs, and you may find them in the upper reaches of the tank at times if you give them the proper accessability.