Selection of a plot in the new development area

What about the brown properties? Are they already taken?

First of all, my congratulations to the planning-savvy community. Clear, unambiguous height specifications (WH = wall height aka eaves height, GH = building height aka ridge height) in connection with contour lines and a dense network of height points create exemplary foundations for planners.

Given the aforementioned praised planning quality, I find the idea good to try to get a plot there (although I generally always advise waiting longer rather than making big compromises). For you, this appointment therefore means not only the beauty competition of the plots for your buyers' favor but also the competition between you and the other interested parties. In this sense, it would mean that less attractive plots would be less contested and your chances would increase if you bet on the underdogs. While I would not take "bad" plots, I might take "second best" ones. With lottery numbers 19 and those in the 40s, there are potentially the most co-winners. For you, that means higher chances for 11 than for 13 (because 13 has the more attractive price-performance ratio), and probably even higher for 12. In this sense, 29 would be safer than 31, and 36 safer than 38.

That you consider "only" 14 instead of all 19 is already good; in a less planning-friendly building area, I would have chosen only half as many. From your selection (modifications see above), I would regard 25/26/27 as first rank, then 11 to 13 and the others you named as good consolation prizes. That you do not fill all 19, I find, as already said, exactly right.

What matters mainly is the slope within the building envelope and then the one within the access route to the front door and garage door, less so the slope of the entire plot. 11 to 13 have the slope from the street to the garden side, 25 to 27 have the incline from the street to the garden side, and for 29/31/36/38/45 it depends on the chosen orientation of the house. 17 is the worst off in this respect, with the slope across pretty much all conceivable house axes.

Thank you very much for the detailed feedback.
It really helped us improve our understanding of the plots.

Do I understand correctly that building plot 9 in the building envelope has the least slope compared to the other plots?
Are building plots 8 and 9 to be equated with the "second choice" 11-13?

Can the slope on the plot be leveled, for example with L stones towards the neighboring plot?

What do you want to build? Have you already considered your budget etc.? What about a basement? Then a slope would rather play into your hands. If you have to calculate tightly, then maybe something flat instead. (I haven’t looked at the plan yet because of the question to you)

We are open whether it will be a square or rectangular house. Currently, a basement with possibly a granny flat is envisioned as a wish. Our budget is around +/- €650,000 and we would like to build solidly. The idea was that we might save money if we commission the trades individually (please correct me if I am wrong here).

What about the brown plots? Are they already allocated?

These places are allocated through the bidding process.

Do I understand correctly that building plot 9 in the building window has the least slope compared to the other plots?
Are building plots 8+9 equivalent to the "second choice" 11-13?

Yes, building plot 9 is a double favorite: your interpretation is correct, and additionally it could be relatively less in demand due to its location opposite a junction. And yes, I also see that it would be comparable to 11 to 13. Plots 25 to 27 have rising driveways, while for 8 to 13 the water would have to be slowed down in front of door and gate (but for 25 to 27 then in front of the terrace door).

Can the slope on the property be leveled, practically with L stones toward the neighboring plot?

People who want to return their brains on their deathbed "with zero kilometers" are heavy users of construction foam and L stones. There are always solutions for people who use their brains. For the said plots, however, it is rather moderate anyway, across the neighbors (the height limits can be read as approximate indicators for sensible ground floor floor heights) it is usually only ten or twenty centimeters (except the eighty between 25 and 26).

So let’s keep in mind this far: 9 and 12 as well as 27 would be my favorite picks, and all the others we have discussed so far at least good consolation prizes. Regarding the intensity of their competition, assume that many of your fellow bidders somewhat naively choose their favorites based on what I would call beginner criteria like maximal southwest gardens.

Regarding the slope, I consider about 1.5-2m once across the plot as the worst case. Far too much to simply ignore, too little to make a proper hillside house.

I recently discussed the 11ants basement rule on "Bauen jetzt" ("With or without basement: a rule as a decision-making tool"). The "worst case" for a slab house is of course the best case for a residential basement house ;-)

We are open whether it becomes a square or rectangular house.

Currently the wish is for a basement with possibly a granny flat as an idea.
Our budget is around +/- €650,000 and we would like to build solidly.

The topography clearly dictates a rectangle with a distinct house axis parallel to the contour lines (and therefore also best aligned with the access road). A residential basement practically implies a “stone” underground floor, even if it continues above possibly in wood. As always, I recommend making the building method decision only during the resting phase of the dough.

The idea was that we would be cheaper if we contract the trades separately (please correct me if I am wrong here).

This is the best way for first-time building owners to pay dearly in learning fees. Use the forum search for my posts with the keywords "Hausbau-Fahrplan", "Gerddieter", "Einzelvergabe", "Eigenvergabe", "Ausschreibung" as well as "Regiestunden". Then I don’t have to tack on reading material for a whole weekend here ;-) (because I have already explained all of that in great detail).

We are open whether it will be a square or rectangular house.

It’s good that you stay flexible. Many already have a 130% idea that they are reluctant to deviate from.

Currently, the wish is for a basement with possibly a granny flat as an idea.
Our budget is around +/- €650,000 and we would like to build solidly.

With a budget of €650,000 (I assume that the incidental building costs are included?), I see a maximum of about 200 sqm living space.
Even if the incidental building costs have already been deducted by you, which in your status is actually still too early to communicate expenses in detail, I don’t see a larger house, so also no granny flat, which consumes living space just like a terrace and parking space.
If you only want to build a 100 sqm house because you don’t need more due to lack of children, a basement or granny flat would also be possible.

The idea was that we would be cheaper if we commission the trades separately (please correct me if I am wrong here).

What is cheaper, in my opinion, plays no big role at the moment, since you cannot save the value of a granny flat.

Regarding the plots:

25/26/27 as the first rank

is also my choice.

then 11 to 13

Isn’t there a high voltage line running through the eastern row, ?
I find 17 great in terms of shape and orientation, but I cannot assess the heights.