I have not read everything now, but I can tell you how we have solved it in the meantime.
We have motion detectors in the [KG] (our entrance area, because of the slope), these turn on the ceiling lights in the [KG] hallway.
Additionally, we have motion detectors in the [EG] hallway and [OG] hallway, these turn on wall lamps near the staircase. This way we have subtle lighting at night and also during the day when we just quickly go to the bathroom. The ceiling lights in the [EG] and [OG] hallway have separate switches.
Our motion detectors are not just normal ones, but somewhat better... That means you can leave them as motion detectors, but you can also switch the light on and off manually, as well as turn continuous light on/off if you hold the switch for 3 seconds.