We have a very similar floor plan - only with us, as in your suggestion, the staircase is shifted to the right. 38-degree gable roof without knee wall - in the stairwell from the step to the roof peak, I have about 4-5 meters,... This makes the bathroom smaller and the children's room bigger - that's how it is with us and perfect (for us). We also built a bay window on the ground floor - without it, it is very difficult to nicely place the dining table. I would have the toilet door open outwards - completely regardless of whether it collides with the front door,... We are fans of the closed stairwell, so with us, the hallway goes all the way to the end of the stairwell - if you push this further to the right, you can manage it too. Then, on the upper floor, there is also space on the left for a shower bathroom, and I would leave out the wall on the right between the bedroom and storage room.