*Spoilers* Anyone feel joining Emet would have been better

[Jandor]

Contrary to what I think a lot of people here think, I believe the writers (mostly Matsuno) are out to make "a cool story" rather than "a coherent story". The continuity is often sacrificed if it gets in the way of telling the story they want to tell. Then there's the fact that there's a lot of different writers involved, writing different stories. The future-telling Echo power you referenced are from the Ivalice and Bozja side-stories and there's a lot of other things from those which don't exactly match the rest of the game either. Auracite is completely different, with a different power. They also required a retcon for Dalmasca since its location and timeline of events was different in ARR.

This basically sums it up. The game has run for nearly a decade, and despite some good efforts from some of the writers, the lore has got pretty messy in places. If you like the story it hangs together well enough that you can make it work, and if you don't like the story there are plenty of loose threads and messy retcons to tug at until it unravels.