if it was me, i'd prefer a standard lockable door for a bathroom. So I'd frame in the 6'x7' opening for a standard interior door.
if the idea is to not close it in, my second preference would be sliding door panels with some sort of translucent glass, kinda like on some closets.
There are many many options, just depends on your preference.
There's plenty of room to either side of the opening for a 2-door sliding arrangement. The walls are thin at the opening, so pocket doors are not really an option. I was thinking a 4-section (2/side) folding louvre door.