I like some of this theory, I think there is a good argument to be made that Shar or Selune is the Absolute in collusion with the Illithids, but then you get to Wyl who has a number of people to corroborate his backstory (including a Baldurian player). It'd be very interesting if select memories were being suppressed by dream-entity in order to make our investigation harder, or better yet to lead our investigation towards being captured again.
I think there is ample material in the game to tell you who Shar is, mostly from Shadowheart, and I also think there is going to be much more on the way.
