Is the involvement of the nature conservation authority necessary for a preliminary building inquiry?

Since the relevant authority already states here that it is an outer area, the §34 probably won't work, no matter which half lies where.

That's why you would need more than just the written word, namely the site plan and the submitted sketches. Supposedly, there is no site plan, but as I understand it, it is necessary for an inquiry?

because the development plan is created for the entire property

No separate development plan is created for a property. It is decided whether one is allowed to build as described or not, or with the mentioned restrictions or changes.

No separate development plan is created for a plot of land. It is decided whether to be allowed to build as is or not, or with the mentioned restrictions or changes.

Or a plan for the development of the plot is laid down to the smallest detail – as happened with our plot. What should one call it? Development plan? Zoning plan? Of course, I do not want to confuse anyone. I just couldn’t think of a better word.

The approval is made by the building authority at the district office. The municipality is only consulted and approves it through the municipal council. They are actually not allowed to decide anything, or does it depend on the federal state? Therefore, your architect should talk to the building authority.