Is a multisplit air conditioner suitable for heating?

Except in high altitude areas, one probably won't experience longer periods below -15°C in Germany anymore. A reasonably insulated house ([Gebäudeenergiegesetz] or higher) maintains a reasonably acceptable warmth for 1-2 days, I think. In this respect, I would only be concerned about the hot water generation.

For water, I am planning a domestic hot water heat pump unless it turns out to be an air-to-water heat pump after all.

Can a split air conditioner also control the room humidity? Which model would that be?

I have ordered the Panasonic Etherea air conditioning units and to my knowledge they regulate the room humidity

I ordered the Panasonic Etherea air conditioning units and to my knowledge they regulate the room humidity

No, they do not. The Etherea only dehumidify and do not humidify. However, there are ways to slightly minimize or accelerate the dehumidification.

No, they don't. The Etherea only dehumidify and do not humidify. However, there are ways to slightly minimize or accelerate the dehumidification.

Ok, thank you very much for the clarification