I don't think we'll get a Witches pack. I think we'll get a Magic pack that would mean you could make witches, but just a tiny bit more general, with different types of witch-craft, After all, we have the Witches' hat and voo-doo dolls already. A ton of Spooky Stuff that came with Vampires and Spooky Stuff. And a CAS flexible enough to make things that are hideous. What we don't have is the ability to learn SPELLS.
Would we have a Witch Lifestate? I don't really think we'd need one. Werewolves would be different.
It would set up for future supernatural packs.