Plot size: 635 sqm
It exists and is okay... how large the buildable area may be is indicated by the floor area ratio. Usually lower in rural areas.
House size: 135 sqm
There is no such thing. There is living area or maximum height, but no size.
The sqm result from the living area on the ground floor plus the living area in the attic above 2.30* height. Everything between 1.20 and 2.30 is then either not counted or only counted half.
*may also vary depending on the federal state.
Number of floors: 1.5
Does not exist - either 1 or 2.
Refers to full floors.
You are allowed to build one story including an attic conversion (gable roof) with a knee wall of max? 1.20.
That means: the roof pitch must be adjusted so that no full floor arises above. Works roughly with anything under 45 degrees.
Roof type: Gable roof
Maximum heights/limits: Knee wall 1.20m
1.20 is okay. There are worse things.
It will simply have a rural building style.