am assuming this is a concrete structure, when shifting service toilet to utility area, and if there are apartments above, then running extra lengths of supply/drainage lines & introducing a structural sink slab (if this is concrete) under the new location can be charged extra.. it will be easier to divide the 3rd toilet. all services will be already available. only, do check on supply & drain pipes capacity as load is increased on the same pipes which were serving one toilet earlier..

That was a hard nut to crack! I've tried many options and this one had the most space. Downside is the bed has to go along the wall. There can be plenty of cabinets in there, but not a large dresser. It would be ideal if your bed could be raised, so you can have drawers/low cabinets underneath it for storage.

Since the lot you describe is smaller than my open living area, I would suggest looking at some of the "shotgun" house plans around New Orleans,LA. I think you can build up and back and get an interesting home with a loft for space. It can be done, A porch with an entry to a narrow hall at the back might work best for you. Will you plan a courtyard (closed)? or what? What part of the country are you in? What are your local codes?

How do you decorate your place, what kind of style, colors, and feelings? That will greatly influence the type of door you might want. Also, think of your budget, and whether you want to install it yourself or hire a professional (you don't need to tell us, just keep that in mind). Then look around Houzz, in the products page, they have lots of interior sliding doors and hinged ones, from elegant frosted glass in a dark wood frame, to rustic reclaimed wood planks. You may not want to purchase that exact model, but it might give you a better idea of what would fulfill your airflow needs without sacrificing style.