Half bath, brings back memories... It looks pretty familiar, but I like the layout better than the one I worked in before we moved. Two questions.
1) How is the ventilation? I had problems with ventilation in the one I worked in because the door was totally NOT lightproof and I had to arrange a blackout cloth darken it. After doing that, there was no way for air to come in and replace the air that was being removed, so the ventilation was, after a while, effectively nonexistent. My eyes don't like fixer fumes, so that was an issue for me. If it hadn't been a rental, I would have made some revisions to ensure that I solved that problem.
2) Where do you put the enlarger? Or are you a contact printer? It looks like you would need to put the enlarger over the toilet, as the rest of the space is spoken for.