Preliminary building inquiry - Developing surrounding land

Hello members
New here in the forum!
For family reasons coming from abroad, I landed in the southwest of DE with my German wife. Originally I am from CH but have lived in NZ for the last 30 years.
I work in the construction industry but have little/no experience in DE.
My wife and I will probably take over the property of the deceased. The house from the 60s is surrounded by about 3600m2 of land.
To pay out a family member and finance part of the renovation, we want to develop the surrounding land.
Are there members here in the forum who might be able to give feedback on my development proposal? I have created a site plan sketch and could upload it here.
Thank you very much

Then upload the sketch.

So I'll try.

I wanted to say something else but was too slow.

The shaded land belongs to the family. The agricultural buildings will be demolished.
The whole land (family) is in the "Gemischte Zone" in the village.
New access proposal
4 new building plots plus the house with ~700m2 land
One parcel remains.
The adjacent land belongs to several owners and is in the "Wohnbauflächen" zone.