Augsburg prefabricated house construction, provider wanted

No, not necessarily. The matter seems to still need some time anyway. If the community already knows the square meters, they probably also already know the side lengths of the property. At least roughly. I would just go there and check at the same time what the west neighbor's name is and if he really wants the driveway up there, what’s going on with the southern access, and of course who the east neighbor is.

Is there already a soil investigation? What does it say?

Site plan

if it is to scale, you can simply measure it using your PDF tool.

There are 269 pages, which also include pictures of the ground because samples were taken.

Should I explicitly search for certain things or is it allowed to upload the PDF file here?

The Bayernviewer has a tool for measuring, here I come to the following dimensions (approx.) 20m on the eastern/western edge 16m on the northern/southern edge