Actually, despite the panoply of mythological stock characters in comics, I can't think of anyone who's created a version of the folkloric Jack Frost (rather than just using the name for an entirely new character), so you're being more original than you give yourself credit for.
![](http://heromorph.com/heromorph2/uploads/smil4353fb0f9c418.gif)
Cool take on him too -- Chaotic Neutral (aka the asshole alignment) is also a great approach for a fun villain. I like that Jack and Jill are not so much evil as just bored. Nice.
![](http://heromorph.com/heromorph2/uploads/smil460ff7f472cd1.gif)