Bumping this REALLY old thread (because I didn't want to start a new one) in case people missed this from Reinheart's recent Famitsu translation:

F: Will FFXIV ARR cover and reveal story that wasn’t really talked over enough in previous FFXIV?

Y: Things that aren’t inside the current FFXIV are the parts I chose to drop, so in general we won’t go deeper regarding these later on. Although, I think we should go over the story surround F'lhaminn and the scenario surrounding Niellefresne. But even if we officially chose to do so, it’ll be further out in future to release this.

So good news, maybe we'll find out who killed whom. Bad news, many loose ends are going to stay just that.