Unfortunately, I'd already bought a lot of materials specific to this closet, so that I don't think I would be saving much at this point going for PVC cages. I will still consider it, though. I don't want to endanger my BP.

Would a discreet fan help circulate out the things that could harm the snake? I don't think it would make or break it, but if there's only a little bit of the cedar oil/pollutants getting into the vivarium, I wonder if a fan wouldn't help get it out. I had seen someone suggest doing it when he made a vivarium for frogs.