For the basement stairs: cabinets, stairs with flip up steps and very narrow stairs. Each step goes up one at a time for each foot. It is sort of spaced so you are putting one foot per step with a steeper step. Very space-saving.
I'm thinking something akin to this for the loft stairs, except with another loft on the other side and the second set of stairs meeting in the middle. "A 355 square feet tiny house on wheels in Felton, California. Designed by Molecule Tiny Homes.