New building with granny flat - general contractor restricts rental and KfW funding

We all do not know what the house of the OP looks like and who is really supposed to use it. As long as two residential units are created,

It was partly mentioned... however, of course it is questionable whether it behaves that way. For the question, one may also stretch the truth a little.

Now to the question: Can the GU restrict both the funding request and the landlord circle?

Yes, I think so. He is the one who conducts the review and takes responsibility for the building application. There is no other authority. The KFW will not control but has its own instances.

By the way, the purpose of the funding is stated by the funding itself, I have copied it once before. You can read the section and then write which aspects support your standpoint.
Everything beyond that is, well, just your opinion.

The construction of residential buildings and the renovation of residential buildings are funded,

I must have overlooked a section about the funding boost for secondary residential units (?).
However, I also have no desire for an endless troll-feeding circle dance about whether the KfW funding is actually only made for an amateur legal dispute and that it is only my opinion that it is actually about creating living space. For all I care, consider it a strange whim of mine to interpret the funding objectives this way:
1. Building "energy-efficiently" beyond the legal minimum framework involves additional financial expenditure – this commitment is to be rewarded;
2. If one does so in such a way that the market is supplied with "more energy-efficient" living space beyond the builder's own housing needs, the reward increases.
Ceterum censeo, an explicit clause, the wording of the funding guidelines should be read with decency instead of maximizing self-interest, should be unnecessary.

Troll feeding ringelpietz

Well, I don’t want to troll either. But the argumentation doesn’t convince me. And therefore I am interested in where this comes from – only with further questions can I understand where I might be wrong.

I immediately agree with your first point, even if the quoted sentence is not complete, ([...], which are characterized by energetically optimized construction and system technology [..]) but fine. I don’t follow the second point – from my perspective, the funding guideline doesn’t care at all who builds what for whom and later uses it. It is purely about the energy efficiency of the object, not about creating living space and the further living space needs of the owner. How I build my house and how many apartments I want to occupy – well, that is – as can be read in many threads here – highly subjective. To me, that all falls under GG §2.

And maybe once again: of course, I don’t mean cases like here in the thread, where the requirements are not met and yet the funding is still wanted.

I believe you should have such details clarified by a specialist lawyer and not in a public forum. That is a fine line to subsidy fraud.