I agree that Kylo wouldn’t admit that about Vader, so maybe change that line back. But, I think the idea that Kylo comes from the light and chooses the dark and Rey comes from the dark and chooses light one of the most interesting parts about them, and what makes the dyad so strong. Besides, it’s not about where they come from, but the decisions they make for themselves. That’s the point of Rey’s story, after all. And if they both have the same origin, what makes Rey’s journey different?