Yoshua, in the second edition of the guide, there is a rule that says that you can use the iconic heros cards as if they were in your class deck as long as they have the Owner trait for one of the characters in the deck.
Flenta says:"when you play a spell that has the Arcane trait, draw a random spell that has the Arcane trait from the box that does not have an adventure deck number."
The psacg guide says: "when you gain a scenario reward if it says to draw a card from the box, then draw it from your class deck." Does this apply to Flenta's power, does she draw a spell from the class deck or from the box?
Have the real PC get amnesia. The doppleganger was also a close observer, perhaps posing as a friend, or even better confidante. A local priest of the PC's deity? Forgive me father for I have lots of secrets I need to share with you.
The doppleganger knows more about how to *be* the PC than the PC does now.