I like the second idea. Or even, as the very first words out of their mouths toward each other (cuts indicated by []):
Darth Vader [] betrayed and murdered your father.
You told me Vader betrayed and murdered my father.
Your father [] became Darth Vader. Your father [] betrayed and murdered your father. So what I have told you was true… from a certain point of view.
Edit: Followup (wrong thread) -
Obi-Wan never told you what happened to your father.
I know, father.
No. I am yo-
I KNOW, I KNOW! [from R2 X-wing scene]