Floor plan optimization city villa + fill consideration

There could be certain requirements in the development plan, e.g. number of floors. Should the

What are you trying to tell me with that?

I don't want to be a spoilsport. But of course the floor plan upstairs will change. You need a staircase to the basement. That is not taken into account in the current floor plan. Because of that everything will change, probably also the static structure.

all these questions should have been answered by your GU/planner, especially if the previously planned house was suddenly thrown out the window from their side. But I wonder why they do that on their own when your plan was largely finished or already submitted to the building authority. Of course, you can't just sneak in a basement, because that would lead to completely new/different conditions/possibilities, not least for the living spaces, entrances, etc. Then you are basically back to almost zero, which in the end could be the better option for your desired planning; it certainly won’t be the cheaper one, and I find it questionable that a basement could be constructed cost-neutral just like that, and I would be interested in the whole context regarding that.

There could be certain specifications in the development plan, e.g. number of floors.

But of course the floor plan above will change. You need a staircase to the basement. This will not be accounted for in the current floor plan.

and that a basement would be created cost-neutral just like that I find questionable or I would be interested in the entire context.

I too am puzzled here, because the site gave no indication for a required basement as far as my sparse knowledge so far goes. To the best of my recollection, this would protrude at most less than knee-high, so far, far from a full floor. The staircase is taken into account and would merely lead further into the basement, where currently a storage room under the stairs is planned, i.e. a broom (or was it a pantry?) closet would be moved from under the stairs into the basement (respectively taking the place of the HAR relocated there). I do not see changes to the existing floor plans regarding the layout as worthwhile even for a penny.

I am also puzzled here, because according to my limited knowledge so far, the site gave no indication of a must-keller. To my recollection, this would at most protrude clearly less than knee-high, so far, far from a full storey. The staircase is taken into account and would merely lead further down to the cellar, where a storage room under the stairs is currently planned, i.e. a broom- (or was it a pantry-?) cupboard would be moved from under the stairs into the cellar (or would follow the HAR relocated there). I do not see changes to the existing floor plans regarding the layout as sensible for even five cents.

Perhaps I expressed myself unclearly and even a cellar to be added underneath would not be a structural/building law problem... In my opinion, at least for me, it would be such that with an already existing desire for a cellar I would probably arrive at a different residential layout and I would also be surprised by the sudden interjection by the planner/construction company AFTER the building application was submitted. But maybe I have also missed something... certainly even, considering the number of pages.

Maybe I just haven't read something.... most certainly, when I see the number of pages

Where else should one be able to get confused, if not in Princess Shiny's thread? - even my otherwise "innate" ability to tell the difference between crazy and nuts, usually typical of people from Cologne, has sometimes been lost here, at least partially.