I think that winter messes with molly to get Harry off balance.  He does not want her part of that court in any may.  The court has shown in the books that they think so little of love and it is easy to manipulate mortals because of this.  A flustered Harry is an impetuous harry and makes grand wonderful mistakes that give us his adventures.  The way I see it is Harry is just an ordanry guy with super powers trying to protect he and his.  Mab is a Manipulative dog of the female persausion.  Going back in time should take lots of power on the same level as the curse the red court had backfired on them.  I cannot see Molly EVER doing that.  I can .. see Mab messing with Molly on general principles because she is.

1. Harry's apprentice
2. the daughter of one of the sword bearers (so she can stick it too God and his Angles).

Harry all in all has been on Gods side.  Molly has been a screwed up kid.  Harry will need more emotional reigns put on him if the Winter court is to control him.  Molly is one, His daughter is another.

Molly cannot be fey.  She was the daughter of a sword bearer.  The very Idea is right up there with my idea that Harry was killed by his freinds who think that that might get him out of being the Winter Knight.

I would like to see Mab try to get her if she ends up being apprenticed to Injun Joe or Grandpappy McCoy.

Just my two cents.

Old Rednek