Hmmm, hard to tell, she's very explicitly not drawing on the mantle, (she draws on it for a second afterward to kick the doors in), though when she gets the boom box and one woman rave going and she's using the same wands she used as a mortal. It may be tied into weather or not you have a soul, that doesn't instantly go away per WoJ.

It probably has more to do with her own mantle. Read Cold Case -- in it, we learn that like with the Winter Knight, the Winter Lady's libido gets a big shot in the arm.

*snip*

So basically, don't necessarily assume it's because Molly is comfortable hitting on Dresden, because chances are it's The Winter Lady being comfortable hitting on The Winter Knight.

Saying that Murphy is the last true blue mortal on the team is a good point. However, her getting so badly wounded by Nic that she'll never recover 100% is also a point where you got to wonder what her future role as "the normal" is going to be in the series. It's fully possible that she'll transition into another role, but given how much her identity has been to be this tough woman, I bet it would trigger even more of an identity crisis than she already had after having to leave the CPD.

Of course, there's also the question of who ends up being the closest vessel of Winter that ends up with the mantle. Toot-toot usually isn't far from Harry, and he considers himself part of winter now, right? That would be hilarious in a way, but also very sad if Mab does something nasty to him in a fit of rage. She's also unlikely to recruit a new Knight anytime soon, as she tries to get Harry back. Whomever ends up holding the mantle may be blocked up in ice for a while.

Molly has lied, and Mab said that the stars will fall out of the skies before she breaks her word.