General question about building planning without a development plan

Even within a "block" of developed plots – that is, an obvious 34 zone without the rear parts of the plots possibly being in the open countryside – favorable development prospects cannot be assumed: such areas are typically expectation zones for the adoption of densification development plans. At first, this sounds hopeful, but the opposite is more often the case: as long as the municipality does not perceive a shortage, it will, on the one hand, refrain from initiating the adoption of the corresponding development plan. On the other hand, however, this is no reason to rejoice: as it does not grant freedoms; rather, it will be argued with "de facto building windows" to largely prevent new developments there. I see using what you call "Hinterland" structurally here as nearly hopeless; more likely to be possible are gap closures within the "de facto building windows." For "more precise" tasseography diagnoses, however, you would have to remove the abstraction from your question. Keep in mind my announcement that I will not comment on cadastral excerpts / aerial photographs with the smallest possible image framing, blackouts / whitening / excessive scribbling: for such childish stuff, my time is too precious.

Tomorrow is Monday, then you can call someone at the building authority again.

Now someone should be available…