Unable to answer "Is this inside a building?" – HP HLi 274 (Fire Extinguisher) – node/13001971056 via StreetComplete 62.1:

Waarschijnlijk in de tunnel dus niet zichtbaar te voet / Probably in the tunnel so not visible on foot

Unable to answer "What’s the structure of this bridge?" – Corry Tendeloobrug (Bridge Area) – way/707009259 via StreetComplete 62.1:

Not sure, none of the structures seem to match.

Attached photo(s):
https://streetcomplete.app/p/320978.jpg

Unable to answer "This shop has been vacant. What’s here now?" – house number 134 – node/2862830133 via StreetComplete 62.1:

Amsterdam Onderneemt Community Space