I don't really understand a lot about this project. Where exactly is this mysterious wall going, where the grill is supposed to go, and so you can enter the house?
Behind the house there is a wall between the soil and the house wall so that the soil does not touch the house wall but that is irrelevant for the [biotop]
Behind the house there is a wall between the earth and the house wall so that the earth does not touch the house wall but that is irrelevant for the biotope
Directly against the wall or with a distance? If you want to put stuff there, then obviously with a distance, but then it is still true that various unwanted things accumulate there and no sun gets in.
Yes, maybe some wood or something will go there. Except on the left side, there is a panorama window facing the forest since the wall is only about 1.50m high