Looking at the layout of your house, I think it will be a nuisance for sims to use the basement bathroom as the house is currently laid out.
Unless there's some aesthetic reason for it (such as maintaining the appearance of the deck), I would suggest lowering the foundation a bit, which will shorten the length of interior stairs going to the basement. If you were to bend the basement staircase in the middle (by 180 degrees) it would still fit in the same basement stairwell, even if the length of the stairs was greater.
I'd also say you might consider shrinking the master bedroom's walk-in closet and adjoining bathroom, and using the resulting space to create a second bathroom there. I like the way your bathrooms look, but they are larger than they need to be to accomplish all the necessary functions.