I've just added Elk Creek and West Fork Elk Creek to the map, based on a hike (https://www.oregon.gov/ODF/Documents/Recreation/Kings_Mtn_Elk_Mtn_Trail_v2009.pdf).

However, I'm a bit confused here.
Does anybody understand why the road going Northwest from here is called 'Elk Creek Road' and the road going northeast 'West Fork Elk Creek Road' while is located on the east side. Additionally, the forks of the Elk Creek coming from Northwest to here is called West Fork Elk Creek and the fork coming from east is called Elk Creek (the main fork). Thus the creek naming contradicts the road naming.

Does anybody have an explanation for this?

This matches with the given of USGS Topo map.
https://viewer.nationalmap.gov/basic/?basemap=b1&category=ustopo&title=US%20Topo%20Download

"the location of this place is .7 miles off"
The place has gone or never existed. This is an auto-generated note from MAPS.ME application: a user reports a POI that is visible on a map (which can be outdated), but cannot be found on the ground.
POI name: Olympus Ranger Station
POI types: tourism-camp_site
OSM data version: 2018-04-17T05:20:02Z
#mapsme

"Dieser Ort existiert ca. 500 m weiter westlich bereits und wurde dort auch eingetragen"
The place has gone or never existed. This is an auto-generated note from MAPS.ME application: a user reports a POI that is visible on a map (which can be outdated), but cannot be found on the ground.
POI name: Olympus Ranger Station
POI types: tourism-camp_site
OSM data version: 2018-07-05T18:22:02Z
#mapsme

2918 road does not go through. Removed large portion, due to wash outs. The 2920 does go through to the 29 road and over to Forks, WA, but is very rough with areas of rock slides which can only be crossed with capable dual sport motorcycles.

Trail needs GPS trace, not listed on any known map.

Trail needs verification, not listed on any known maps. Needs GPS trace.

Trail needs GPS trace, not listed on any known map.

Survey for direction a existence. According to STRM data (seen with OpenCycleMap render) the stream would be going up and then down the hill...

align and improve geometry. At the time of writing Bing seems well aligned with the GPX traces in the area

Survey for direction a existence. According to STRM data (seen with OpenCycleMap render) the stream would be going up and then down the hill...