Bungalow on fire wall

Hello everyone,
thank you for your patience with me. I’m trying to organize everything a bit here because it has become confusing by now.

I got the most recent (1943) land use plan from the city.

Unfortunately, that was the only plan I received.

The buildings marked in red will remain.

The area marked in green is meant to indicate the driveway. The blue line is the boundary to the garden; no construction is allowed beyond that towards the garden.

I also included the house on the street to clarify where the driveway is located.

That means, it could already be a U-shape, or two offset rectangles could be used if it sells well. An L-shape is also conceivable, but the long leg must be built along the firewall.

Layout and dimensions probably don't fit us, but I googled something similar because I find it hard to describe the offset rectangles. This is how he briefly sketched out how he could imagine it with a flat roof.