I think the mission givers(NPC) thought they were on to Raxxla with the SAP8, crystal maps. In reality they seem to be very similar to Guardian technology.
From FD perspective the missions served a dual purpose of sparking interest in Raxxla and foreshadowing the Guardians. We will never know the full story, because the first Guardian ruin was discovered before the planed narrative had time to play out.
The E/F missions were cut when they no longer had a function in the narrative.
A journey can be anything. We always have to do them our self(unless mulicrew works).
I suspect the SAP8 containers provide crystal maps (Guardian tech?), possibly to Soontill which may or may not be a Guardian homeworld or Arkship destination.