So after a couple of weeks of steady work on the home design I have some results to share. The design below meets most of our requirements–although it is larger than we were shooting for–the interior footprint is 720 square feet.
The floor plan below shows the beds with a desk on top of them. It actually is the other way around. The beds would/could be lofted to make space for the desk.
The height from the second floor to the peak of the roof is about 15 feet. This allows us to create 3rd floor loft space.