Isn't there a tiny possibility that the connections between the different bungie games are more loose. Isn't it possible that instead of inventing a new story for myth, bungie lended a piece of story from one of their other games and a piece of story from some good books. They just changed the names a little bit to fit their new game.
I don't think that bungie planned that when someone makes this or that in the game, it is not what it seems to be: it is that race of ancient evil from their sci-fi game that comes back. There is no proof that the connections actually exists and aren't there because bungie (being lazy) just copied story, with small changes.
Honkem