I can't understand most of Shane's posts either.

Rhapsodies is looking to be wrapping up each storyline in sequence, so doing the Rhapsodies missions for the core game to unlock Trusts in the Maat fight shouldn't spoil anything about Zilart or Promathia, but we'll see when it releases. If they're releasing the rewards like that, the logic says it should be before you need it for that progress in the storyline.