Single-family house, approx. 140 m², 2 children's rooms - What do you think of the floor plan?

I would find that ideal for you.

How do the Grantlhaua plans come to your mind here of all things? - apart from the expectations for the building, I do not see the plots comparable anywhere, so I am surprised.

The upper floor walls are only 11.5 cm thick,

To me, it looks like a collar beam roof, so I consider that not unlikely.

How do the Grantlhaua plans come to your mind here?

Did I get lost in the thread? Garage top left on the plan, direction south-southwest bottom right on the plan? Wasn't it like that?

I'm just looking – bottom right on the plan was southeast. Then I was indeed mistaken.

After a conversation with the architect, here are the revised plans. Several changes have been made. The windows are arranged differently (thank you for the suggestions), the hallway has also been enlarged by the now more open staircase, and even the very small window brings in a bit more light. The kitchen door has been rotated. We do not want an exit to the outside from the living room. The entrance area will be paved at ground level, so there will be no front door platform. We are still a bit unsure about the guest WC, whether this variant is actually the solution. The rotated door makes more sense for the property, but after thinking it over for a while, we will probably want to rotate it back in favor of the second tall cabinet. Otherwise, the area for the stove and work surface on the right/left (on the wall to the pantry) would be very limited. What do you think? The ground floor plan includes the windows from the following south view. In this proposal, the windows in the guest WC and pantry are smaller (parapet height 1.25). We like the external view much better now than before due to the changed dormer and the double window above. However, it should be noted that the drawn windows here do not match the floor plan (criticism of the architect is justified). The gap between the guest WC and pantry is too large. The pantry window therefore appears further to the left on the exterior view, similar to the kitchen window. From the outside, this also looks coherent (bathroom window to kitchen window), but the kitchen window is now very far to the right, so it will probably be difficult to plan the sink appropriately under the window. We will probably move the kitchen window further to the left so that the gaps between the three windows below are at least equally sized and the kitchen window fits better with the kitchen layout. Then it is not symmetrical to the bathroom window, but it is more important to us that it fits from the inside. Alternative: We tend to the solution of having only one simple kitchen window. What do you think of the variant with only one kitchen window and smaller windows in the pantry and guest WC? How do you assess this visually? In the upper floor, the wall to children's room 2 should be a 17.5 cm wall. Simply to provide a little more soundproofing to the toilet/shower. Even if it does not help very much, it is probably better than the 11.5 cm wall. Also, we want to move the door slightly further to the right so that there is a bit more space behind the door for a laundry basket/wardrobe. We now find the wall near the toilet somewhat short, do you see it the same way? The knee wall was raised by 20 cm. Here are the remaining views: Windows now more coherent?! North view – not nice, but we are not bothered by that. We look forward to your, gladly also again critical, comments. Many thanks for your efforts!

I find it nice that the planner keeps providing an update, but as long as you ignore the criticism of the, in my opinion, ridiculous slants of the pantry as well as the misplaced chocolate location of the same in the house, I'm out of here. The strict separation of living room / dining area is also very incomprehensible to me.

I can very well understand the separation between living and eating/cooking.
However, I still find:

[*]slanted pantry
[*]narrow staircase .. have you ever had the walking width calculated?
[*]zigzag at the entrance ... i.e. the wardrobe does not look particularly good there

not successful at all.

In addition, in the upstairs bathroom the sink is drawn with approx. 30 cm depth and thus does not correspond to reality. I would dissolve the T-solution there, because as the shower is currently drawn with 90x90 and a door, the whole T somehow seems obsolete.
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On the assumed basis, I would take about 30 cm away from the living room and thus also the bedroom and give it to the staircase. The staircase would then not have a rough dimension of 200x200 cm, but rather 230x230 cm.
Possibly a small storage room in green at the staircase ... alternatively accessible from a corner of the utility room, maybe also the space under the stairs, since I have rotated the staircase. The entrance opposite the slightly shifted kitchen entrance.

Slant of the pantry removed, entrance door further towards the top of the plan, then a proper wardrobe of about 175 cm can stand in the corridor in front of the WC, which is completed around the new corner with a small seating area and hooks for the daily/guest wardrobe.

In the kitchen, a 160 cm tall cabinet also fits, door still hinged on the left, you can just put a stopper there.

Upstairs bathroom restyled once, whereby the green walls are supposed to symbolize half-height walls. Red is a towel radiator. I would always make sure that if you install a shower door because you don’t want splashing outside the shower, then the shower door should make SENSE to open inward so that the water running off the shower door doesn’t end up outside the shower again.

In the bedroom, the door further towards the top of the plan, then the space behind the door can still be used for a reduced-depth cabinet and the other cabinet can be longer because you do not bump into it anymore. On the left side of the plan then a dresser.

I agree with my predecessors, why do the guest toilet and pantry face south while the living room is located in the northeast? Do you spend time there more often between 6:00 and 9:30 to make use of the morning sun? If you consider the south-facing sun in the guest toilet absolutely indispensable, as a last resort I would at least open up the living room to create a large L-shaped area.

The T-bath in the last draft doesn’t look that bad. I would give the children's rooms significantly more window area (larger double windows or skylights), otherwise they will become quite the stalactite caves or "living rooms"...