Unable to answer "What are the opening hours here?" – Tiiristupa (Cafe) – node/670301510 via StreetComplete 61.1:

Seems to be a kiosk not a cafe. Looks like it hasn't been open for a longer time.

Unable to answer "What are the opening hours here?" – Gullkrona Sattmark (Gift Shop) – way/313741165 via StreetComplete 61.2:

There seems to be another shop. I think it is called "Tjockt". It was closed and I did not see any sign with opening hours.

Unable to answer "What’s the surface here?" – Foot Path – way/1192998976 via StreetComplete 61.2:

These are more locations to sit together than short paths. The other short paths north of this one are the same.

Attached photo(s):
https://streetcomplete.app/p/299428.jpg

It seems that ferry 82 takes a circular route (Slussen->Ällmänna->Skeppsholmen->Slussen) and not a round-trip (Slussen->Skeppsholmen->Ällmänna->Skeppsholmen->Slussen). Also Skeppsholmen seems to be an optional stop, but I don't know if that can/should be mapped.

"Was not able to locate it anymore."
The place has gone or never existed. A CoMaps user reported that the POI was visible on the map (see snapshot date below), but was not found on the ground.
OSM snapshot date: 2025-07-13T12:01:25Z
POI name: Robert's Coffee
POI types: amenity-cafe
#CoMaps android

Unable to answer "What’s the surface here?" – Tennis Court – way/482078982 via StreetComplete 61.2:

Here is only one tennis court, not two.

Unable to answer "What’s the surface here?" – Tennis Court – way/482078981 via StreetComplete 61.2:

Tge surface is sand, but this place looks avandoned.

Attached photo(s):
https://streetcomplete.app/p/300105.jpg

"Duplicate"
The place has gone or never existed. A CoMaps user reported that the POI was visible on the map (see snapshot date below), but was not found on the ground.
OSM snapshot date: 2025-07-13T12:01:25Z
POI has no name
POI types: tourism-picnic_site
#CoMaps android

"Here is just the cafe and the reception"
The place has gone or never existed. A CoMaps user reported that the POI was visible on the map (see snapshot date below), but was not found on the ground.
OSM snapshot date: 2025-07-13T12:01:25Z
POI has no name
POI types: shop-convenience
#CoMaps android