Honestly, the dream would be a full on origin story a la Dragon Age Origins, though I understand it's inefficient. The minimum should be the Pillars of Eternity early conversation laying things out. It wouldn't be hard to do as part of the "Who are You" character creation. The Tadpole asking you questions and such.
Yes, exactly. Tadpole could be one way, probing the character's mind for some background choices. There's even some background options in the D&D Player's Handbook that could be incorporated: personality trait, ideal, bond, flaw. And Pillars style dialogue where party members ask a few questions relating to your chosen background would work quite well and it'd be relatively easy to add. Even if the answers are not used anywhere, this would give the custom player character a much better sense of identity and history.
