Moose, I don't think those other people you see in that first Echo scene with the Mothercrystal are meant to be anything other than fellow adventurers - if you pay close enough attention one of them looks like that female elezen ARC you later see during the level 15 dungeon quests (the one who accompanied Arvere and Edda). The roegadyn MRD I'm pretty sure is also later seen in the same way and is not meant to be that Rhaglr-Archon long rumoured because, well, that would kind of be silly.

So yeah, I think that scene is just to show that the player 'is just one of many chosen by Hydaelyn', even if later events kind of throw that idea to the wind.