Furnish the dressing room, which, if I see it correctly, should also include the wardrobe. Consider where you would stand to change and how the paths would be, for example, if someone wants to go to the bathroom. Although the room is so large, it doesn't work for me. I would rather go for a well-accessible bathroom for everyone.
Regarding the bedroom toy: a mattress gives way, sliding a sliding door over it will not provide a satisfactory solution. Either you have a gap when you lie on it, or the mechanism jams when you don't lie on it, or it rattles when you turn around. The bed will eventually need to be replaced, and then the height will no longer fit. My conclusion would be: it might have sounded like a fun idea at one point, but it is impractical. Bringing in and assembling a double bed there will be demanding, if possible at all. I also find the short wall ugly because it squeezes in like that. To disturb as little as possible, you have planned a dressing room for changing, and if someone wants to sleep separately, then complete separation is certainly more pleasant.
Regarding the kitchen and windows: Keep in mind that you gain nothing if the window disappears behind cabinets. It is not impossible to set up a kitchen on a 2.50m width; this exists in terraced houses quite often. But you are talking here about a 200 sqm dream house and have all options open, right? It is also simply a bit odd to have the narrow hallway there and then the kitchen passage parallel to it.
Please, please, please do not fall too much in love with the current floor plan. I simply don't believe that all the described problems can be fixed by shifting a wall by 10cm. Probably not structurally feasible either. Neither the upper floor nor the ground floor seems consistent, neither as a two-apartment solution nor as one.
Regarding "what happens after 10 years." Option A) one or both children stay in the house longer than expected. Option B) parents find a new hobby and are grateful for the extra space. Option C) one finds a solution then, so they know what they really need in terms of space. Option D) one moves again to something smaller. Option E) one tries to keep a few places adaptable (e.g., making the staircase separable) but does not design everything around an unforeseeable future need. You could possibly just plan smaller now if you focus on what you need now and do not always keep in mind "if we separate this, then a kitchen could go here."
- If the 2nd door in the bedroom is removed, another wardrobe could be placed in this area. If I plan with 2 wardrobes opposite each other, there would still be 1.3m of space between them, which should be sufficient for 2 people to pass each other. Also considered was the idea of using a hinged door with a mirror if you want to see yourself from further away. I no longer believe the room would necessarily always be used as a "dressing room" but rather as a storage room for clothing. The clothes would then be taken out and prepared in the bathroom, possibly showered first.
In principle, the bathroom could also be placed in the center, but then the entrance door would have to be moved upward, which I do not really like. That way, guests would always have to walk through the dressing room.
If so, the bathroom would have to be moved to the lower corner, but then the path from the bedroom would be the same as the current path for the children. Also, the laundry chute would no longer work. And you would have to go through the hallway to get to the dressing room.
The children's bathroom could also be dispensed with as it stands; in my opinion, it would not be a catastrophe if the children had to walk 5 instead of 2 meters to the bathroom.
- As your predecessor already said, the noise insulation would probably be insufficient to have real benefit. As mentioned, it was/was supposed to be a gimmick, but it probably won't work as desired. (Regarding the previous thought: the drywall would only have been installed after the bed was placed; between the door and bed, one could have placed fabric tubes like those used under door gaps, but a bed replacement would then really be very problematic.)
- Regarding the kitchen and windows, I am not exactly sure what you mean. With 2.5 meters width, 2 kitchen units leave 1.3m free in the middle. If a 1.5x1.0m window is placed centrally, in my opinion, this should be sufficient. As said, a lot of light also comes from the dining room.
I find it practical to be able to store groceries after shopping either in the utility room or directly in the kitchen. Likewise, you can also come into the kitchen directly from the front door if you, for example, do not come by car.
- This is my 12th version/layout, so I have already discarded quite a bit. Therefore, I am certainly open to changes. Still, I like this draft best so far because I would have to make the fewest compromises here. You will probably never find a completely perfect plan.
A) Exactly for this reason, it would be useful if both floors could be used separately.
B) What hobby needs 90 sqm? And if so, you would probably have to tear down all the walls ^^
C) Once the house is built, you cannot easily make changes (if not planned before). You also have to consider cables, pipes in the walls, etc.
D) If this happens, you would then have the option to rent out two separate apartments. I assume it would not be so easy to rent 200 sqm to just one person/family.
E) There are not that many changes now; on the ground floor, a partition wall would be built for a bedroom, and upstairs the partition between the children’s rooms would disappear, so there would be a living room with open kitchen. Theoretically, you could even keep the partition wall, but then the living room would be too small.