More on NaNoWriMo and Beauty's Story

I'm really enjoying writing my Beauty and the Beast retelling.  It's nice retelling a story, because I have all of these major plot points already mapped out for me, and I just have make sure to get all of them.  At the same time, I am free to add little twists, new pieces to the plot, new characters, even new settings.  The danger, of course, is that I will borrow too much from someone else's work.  And I am on my guard against that, because I have read a lot of retellings of this particular fairy tale.  But the addition of new characters, of an aunt, and a much younger sister, is changing the fabric of the story.  It's like I can see the story all mapped out, the normal progression of events and this person does this at this time and this person does this at that time, and by adding new characters, all of it changes subtly.  I can do new things, and things that I have seen other authors do are not possible for me anymore.  The original map is a little obscured, because I honestly don't know what the final affect of adding a little sister is going to be, but I know it is going to be different.  And I'm excited to see the final product.