Plot selection in the new development area for single-family house - ranking

If we could freely choose, we would build a classic - often found here in the region - gable roof house with a steep pitch (over 40%).

Very wise decision. I support the resulting attic space as storage or even as an option for a hobby room or office.

however, the following restrictions:

?

So a "classic gable roof house" should actually be possible.

Absolutely!

so that the upper floor does not become a full floor due to the slopes and that an expandable attic is created instead

You can, you have all possibilities except for the maximum height of 11 meters.

Due to the ban on dormers, a nice bay window would unfortunately not be possible.

You are allowed and able to create bay windows on the ground floor.

Am I overlooking other sensible options?

I think you are overcomplicating things. For you as a gable roof house builder without the interest in building two full floors, all options are open to you.

Ultimately, a visit to the architect is planned, but it would simply be nice to get a few basic ideas in advance.

A (freelance = without quotation marks) architect should not be prejudiced by anything brought along at all – regardless of whether it is already mature floor plans or "basic ideas." Many prospective builders probably have the thought stuck in their heads to make up for part of the waiting time for the land allocation by taking a flying start / starting off in second gear – but that’s nonsense. Or is this the impatience of expectant fathers whose watch in the delivery room moves too slowly?

Due to the ban on dormer windows, a nice bay window would unfortunately not be possible.

Here I am completely at a loss as to what (presumably: supposed) causal connection might be meant by that.

Due to the ban on dormer windows, unfortunately a nice bay window would not be possible.

I'm not quite sure what a bay window has to do with the roof structure. But maybe you mean a cross gable. In my opinion, that is not excluded. Or is the 3rd or 4th gable also a roof structure?

As a layperson, it's not that easy, even though I believe that through years of reading here I have of course picked up a lot. I have repeatedly read the development plan over the years during the process up to the statutory resolution, and the classification

F9 Roof pitch
Above the second or third full floor, flat roofs or shed roofs with a roof pitch of 22° to 30° are permitted.
Alternatively, recessed stories with a flat roof or a gently pitched roof up to 16° are permitted; garages, carports,
and ancillary facilities according to §§ 12 and 14 of the Land Use Ordinance are only permitted with a flat roof.

was basically for me: "okay, only flat roofs and shed roofs are allowed". We actually don't want the former, so it has to be the latter. In retrospect, the aspect that it only applies above the second full floor is of course clear, but somehow it was always stored incorrectly.

By bay window I probably meant cross gables like those seen, for example, on the "Lichthaus 152" or many other standard floor plans. With the classification

F 11 Dormers
Dormers, roof extensions, and loggias are not permitted.

I assumed that any possibilities to "break up" a corresponding gable roof above the first full floor upwards for the purpose of gaining space are not permitted. Am I also mistaken here?

okay, only flat roofs and shed roofs are allowed

I think you are overcomplicating it. For you as a gable roof house builder without interests in wanting to build two full floors, all options are open to you.

Mea culpa! I must have been confused when I wrote #37. Forget it. Thank you. Gable roof is not possible.

Am I also on the wrong track here?

From your quotes, I read the clear intention of the development plan issuer to prevent excessive building volume. I would not yet deduce an exclusion of a transverse gable in the attic as the first upper non-full floor from this.