I just wanted to ask about the floor plan first and not lay all the cards on the table.
People like me can be switched from helpful to angry with this simple trick, plus you regret giving advice based on false assumptions. You can now strike my sentence about the peanuts, but the suggestion about differentiation you would now have to think one dimension higher. On the "new business basis" I would now advise completely differently: my previous advice now applies to the two outer semi-detached houses; in construction phase I I would put a two-family house in the middle, with integrated garages on the street side, a garden-side granny flat on the ground floor, and on top a "bungalow"; in construction phase IIa a semi-detached house on the left side of the plan, and in construction phase IIb demolish the old garages and put a semi-detached house on the right side of the plan.
The only thing is the power supplier is being stubborn and wants a connection for each half
Nonsense babble. A multi-family house does not need multiple connection rooms just because it is spread over three building bodies – at least not as long as you do not subdivide the property. I renew my suggestion of a central house connection room and add the recommendation to consider the keyword combined heat and power plant. By the way, the project is slowly reaching stages where 1. your inheritance planning would require a specialist, and 2. it should be an honor for semi-detached and two-family house providers to submit proposals to you.