after all that work man, that hurts. My wetroom is sealed off from the house, is yours? Even the door is an exterior door with weather stripping. There is virtually no way for the moisture to travel into the house, which is a major reason why I went with in-wall. I know there were design considerations in the way you set up your system, but maybe you could alter the in-room part with resin sealed plywood sides and top, at least until you figure out how to proceed.
Mold really isn't so foreign to us but when we see it, we tend to panic. I reality, there is mold all over the place, and all over our bodies in some form or another. My wife freaked when she saw all the dead mice in the wall I took down, but really our homes are full of all kinds of organisms. Don't let it kill your system!!