You haven't received very many replies, which perhaps means there's no really good solution. I would consider turning the bath into the walk-in closet and putting built-in drawers with shelves above where the closed off crawl space. This would create a dressing area in the upper left corner. Then put the bath in the upper right corner, up to the edge of the balcony and the window. You don't say what you need in the bath, but the space available would be about 9 ft. square and perhaps big enough for your needs, and it could be longer if you forego the balcony. The plumbing might be an issue over the unheated space and would have to be carefully worked out.
Q