Floor plan optimization city villa + fill consideration

How would you furnish the children's rooms or place the side windows for the children facing East and West? I am unsure about the furnishing and afraid of losing usable space due to an unfavorable window placement. Do desks always have to be placed by the window? I find Child 1's room easy to furnish. That's because the wardrobe disappears behind the door. Unfortunately, that doesn't work for Child 2. Therefore, it is more difficult there.

I would definitely make sure that the desks are placed in front of/next to the window for as much light as possible. Keep in mind that depending on the time of day, it may be shaded in the summer.

I wouldn’t make a tiled shower wall in the master bathroom. Use glass, it makes the room look bigger. However, where you want to store all the makeup, care, and toilet items in the master bathroom is a mystery to me. A shower in the guest bathroom is completely unnecessary and only takes up space. Do you really want to clean 3 bathrooms until old age? Even if 2 of them aren’t used later, they still need to be cleaned from time to time. Sacrifice the shower on the ground floor and make the wardrobe bigger!

I would swap the toilet and washbasin in the master bathroom and extend the dry/installation wall completely along the length and height so that a large mirror cabinet can be installed.

I would swap the toilet and washbasin in the master bathroom and extend the drywall/installation wall completely along the length and height so that a large mirrored cabinet can be installed.

Good idea with the built-in mirrored cabinet. But why would you swap the washbasin and toilet for that? Isn't it possible as drawn? If I were to swap the fixtures, I would have to move the door to the master bathroom down according to the plan. Then I wouldn't have a corner left for storage space. I was actually considering putting a laptop table there.

I will sacrifice the shower in favor of a larger wardrobe. How big is a comfortably sized guest toilet? Is 1.8x1.6m enough?

In the master bathroom, I wouldn't make a brick shower wall. Use glass, then the room looks bigger.

I want the brick wall for plastering reasons. I want to make everything as easy to maintain as possible. I also don't like silicone seals. You would always have those with glass, right? Do you actually have them with a half-wall and half-glass wall as well?