Eaves height and roof shape in new construction planning

The development plan says yes here max. 2 floors, not (necessarily) 2 floors.
By the way, a basement may also be executed as a full floor. Then with ground floor plus roof, it results in a conditionally nice 2-story building.
A city villa can be a 2-story building, but a 2-story building does not have to be a city villa.

"conditionally beautiful" I'm rolling away. But the idea of a half-buried city villa is delicious, can someone please paint that?

But the idea of a half-buried city villa is delightful

The eaves height refers to the ground floor floor level, and its maximum value is individually set for each building plot. The regulations suggest that the building plots have a slope of 2m - 3m. Since we neither know the orientation of the building plot nor the existing heights, we do not know whether it has to be half-buried.
So let us wait and see if the original poster provides a useful basis for discussion.

Tell me - simply in text format instead of a link - so "Posemuckel No. 815 in the meadows" as the development plan is called, then we can google it

It is about building plot No. 1 in the development area "Im Haferkamp" in Ostercappeln.

If you google that, you will find the complete development plan including all details.

Does that help, dear sir, to clarify the remaining open points?

Yes, it looks bad for your plans. Obviously, the terrain slopes quite significantly downwards to the north. The regulations are based on that. I haven’t found a height plan yet, but two stories are actually only allowed or reasonably possible in the already mentioned form of a basement located on the slope, which protrudes halfway out of the hillside.

Two classic above-ground full floors will hardly be feasible in a reasonable way. But, for example, a shed roof facing the slope would offer quite a lot of scope for development and light at the same time. You would just need to know how high the prescribed height of the ground floor is above the top edge of the terrain and how steep the slope is in your building plot. The downside of the north roof variant would be its unsuitability for photovoltaics if that is an issue.

This is about building plot No. 1 in the development area "Im Haferkamp" in Ostercappeln.

This doesn't seem completely unfamiliar to me *thinking hard* - not only because is building "next door" in Knolls Wiesen.

The regulations suggest that the building plots have a slope of 2m - 3m.

Yes, the reference height here is 107 m NHN compared to 110 m for the "right" and 104 m for the "left" neighbor.

What the "a" ("deviating building method") behind the II for the number of floors in the development plan means, I did not see explained.