Unable to answer "Do you have to pay to use this restroom?" – Restroom – https://osm.org/node/12874781762 via StreetComplete 62.0:

idR abgeschlossen
also nur bei Nutzung der Hütte verfügbar

Attached photo(s):
https://streetcomplete.app/p/318963.jpg
https://streetcomplete.app/p/318964.jpg