Vanilla is a product of Lussumo:
Documentation and Support.
How much explanation does it need?
As for the 6 in Baltar's head, it has - near as I can figure, anyway - nothing to do with the reporter (which doesn't mean it would pass up on a chance to fuck with Baltar). As for "what the deal is" with the head 6 and Baltar... well, the show's not over yet. I've certainly never gotten the impression that she actually enters the real world, though, whether by religious bullshit or some other mechanism.