Can a single-family house be sensibly planned on this plot?

Not entirely correct - it is completely irrelevant whether the mayor or the municipal council like the house or whether they THINK it fits or does not fit into the town. That was our problem: the council and mayor were strictly against it (different ridge direction, something we had never seen before, too modern, etc.) The higher building authority (LRA and thus ultimately the decisive body), on the other hand, said: all legal requirements fulfilled, it can be built like that.

The taste and liking of the mayor and council can never, ever be a decision criterion - where would that lead us.

The hassle from the municipality cost us a total of 2 years, but in hindsight it was worth it - we could build the way we wanted. I admit, however, that it was nerve-wracking and at times I was completely exhausted and almost gave up. Our architect was always super cool then. He always said: we’ll get this through - there is nothing legally against it.

We also went to the municipal building office in advance, asked, coordinated, etc. But the employee in the building office is not on the council and they just did not want to (and also couldn’t really read plans properly - it was simply indescribable how much stupidity was concentrated in such a small space. I still shudder when I think about it).

The end of the story was that after repeated rejection by the municipality, the responsible officer in the LRA building office sent a clear letter to the municipality explaining why the building can and must proceed that way. So that was the poor guy who then had more work because of it. Then you have to wait for the deadline during which the municipality has the possibility to file an objection through the administrative court. My nerves were pretty shot by then and I was trembling, but our architect was still the coolest guy ever and just said: just wait, the administrative court follows the statement of the higher building authority. The municipality would have to have very good arguments for that and they don’t. And he was right.

The municipal council had passed the plan without even looking at it. We were at the town hall beforehand with a few pictures, still far from the plan.

We built as we wanted, without conflict, without trouble. A clarifying conversation in advance costs nothing. A few arguments to change minds don’t either. Whether they have the authority to decide or not, whether they have any idea or not, they can make life difficult. Even vague guidelines like "The village appearance must not be affected" or "de facto building line" (which we adhered to with much imagination) leave room for obstacles.

But apparently only one full storey will be approved on the property (there was apparently also a preliminary building inquiry for this, single-family house with 100m2 footprint).

Then get its plans and see how this house could hypothetically be enlarged to the desired 150 sqm within the approved framework. Incidentally, the tip has already been given on how the low-height living space could preferably be accommodated in ancillary rooms. Apart from that, I am always amazed at how the restriction of the second non-full storey already causes intimidation, before it is even clear whether one could need more than 40% of their total floor area in the attic.