ATMachine said:

Yeah, as I said, originally Luke and Leia definitely were not twins. The question of them not being related, however, may be another story entirely...

So that begs the question: does it ever say that Luke and Leia are twins in the OT? I remember it saying that they're siblings, but I don't recall it ever stating that they were twins or even born near the same time.

If in the OT they're only considered siblings, your re-write could have them be born completely separate, with Leia being with her mother and Luke being wherever you please