In one cutscene for a class quest (can't remember which one) you get seen while using the Echo, and when you come back to the present day the person you were watching (and saw you) remembers you from it, so therefore it must actually happen, or you are implanted in the persons memory. I would suggest you don't try to think on the temoral paradoxes too much, it gets rather painful.
But it is possible that the twelve use the echo to contact the path of the twelve and tell us how to survive Dalamud, possibly using the echo, and with the guidance of the twelve we can save life on Eorzea while scaring the planet.
I think adding the twelve telling us how to survive will be a cool idea, also lets go back to the starting cutscenes, the voice you hear that says "Hear, Think, Feel" has it been said who that was, was it something to do with the echo?
If it hasn't been said, what if its one of the twelve using our dormant Echo to contact us, to see if its possible before this came in preperation to help us, That one just came to me.
