Sorry if I’m joining in very late and haven’t read everything up to this point.
Still, I have to question this mouse-tunnel entrance planning again. It’s a terrible space-waster and you still constantly feel cramped. It’s also as dark as a tomb. Please free yourself from this compulsion that the garage has to align with the back of the house – I see no reason for that. Put it to the back, move the entrance and gain space for the entrance area, hallway width, extra shower, and living room door. Also, I would enclose the last step of the stairs (it disappears into the ceiling) and push the living room wall as far as possible into the hallway to make use of every centimeter for the tight dining area.
The bathroom upstairs is a disaster, but you have already realized that yourselves. However, I also want to point out the almost unusable storage room (in case no one has done so yet). It offers no space to actually store anything. That narrow “little shelf” behind the door is ridiculous. I would reduce the bathroom and child’s room each by a few centimeters so that a 60 cm storage space for the wardrobe is possible. Move the window and door so that they don’t get in the way. Adjust all the other windows accordingly.