Is the plot suitable for a narrow house for 5 people?

I can very well imagine this seemingly detached semi-detached house, as it will probably only be a detached third twin to the semi-detached houses standing directly next to it (however, in the development plan excerpt, I see neither plot lines nor clearly recognizable usage template allocations).

All right. Until now, I had assumed that "half semi-detached house towers" would not be built very often. But of course it makes sense to adapt the buildings to this environment. I will talk to the building authority.

Inspiration you can look for anywhere on the internet. For example, for a full storey on the upper floor (then a complete attic as sleeping/work space, ground floor classic living/dining/utility room). And that on 6x9m. If you make bathroom 1 a small office or the utility/heating room, you get even more space in the attic/ground floor)

But that is also a horrible floor plan that discourages building. Who comes up with something like that? Is that 40 cm between the sink and the corner in the passage? And hardly 2 m of wardrobe for the parents? And the kids' room, like a cheap cabin on a cruise ship?

Inspiration you can find anywhere on the internet. For example, for a full floor on the upper floor (complete attic then bedroom/work, ground floor classic living/dining/house connection). And that on 6x9m. If you turn bathroom 1 into a small study or the house connection/heating room, you get even more space in the attic/ground floor)

Yes - that would fit well (parents incl. work in the bright attic). Preferably, of course, without a basement. We'll still have to squeeze out some storage space (or have Marie Kondo help with the move).

But that is a spooky floor plan that discourages building.

No, a typical semi-detached house floor plan for families with a limited budget and/or small plots.

Exactly the statement you made is the basis for the saying at the regulars' table that no one can afford a house anymore. This is space utilization and is not meant to win any beauty awards. By the way, millions of tenants also live in such floor plans as apartments. It works very well.

All right. Until now, I had assumed that "half semi-detached house towers" would not be built that frequently. But of course it makes sense to adapt the buildings to this environment. I will talk to the building authority.

Talking to the building authority won't be necessary here (since the plan is clear in this respect and requires no exemptions) and therefore makes little sense, as the neighbors will be the ones you need to talk to (and the building authority may only give them your contact details, but not vice versa). Network yourselves, it's not difficult.

But that is a creepy floor plan that deters building. Who comes up with something like that? Is that 40 cm between the sink and the corner in the passage? And barely 2 m of closet space for the parents? And the children's room, like a cheap cabin on a cruise ship?

With the usual suspects, that is tried and tested – which is why the models resemble each other so much. The best thing for the children, besides age-appropriate playmates in the same street, are above all parents who are not kept awake at night by the capital service for a stylish Neuschwanstein. What Jürgen Rüttgers once bluntly called "children instead of Indians" essentially requires residential property developers offering options for families who secure the prosperity of retirees. An economy cannot live on a handful of Geissens. 140 sqm for a family of five is not "(a)social housing," but bread-and-butter architecture for everyone. Affordable housing costs and golden faucets are "natural enemies" of each other.

... bread & butter architecture for everyone. Affordable housing costs and golden faucets are "natural enemies" of each other.

We hope to reach around 160/170. In the latter case, we would then be at 800k€ (land + 3500€/m2) and a capital service of about 4000€ per month. Just as context for the discussion.