Re:What is Six
The Caprica 6 that fought with Starbuck said some things during the fight that suggests she has some knowledge from the Galactica, for example she hinted she knew Starbuck and Baltar had a thing happening.
The Fleet 6 that accused Baltar as being a traitor gave no indication that she was a Cylon, even when she was alone with Baltar in the bathroom. I beleive that this one didnt know she was a Cylon, then again, how did she dissapear.
The Galactica 6 is frustrating, no sooner we are convinced she is Baltars imaginary freind something happens to suggest she is more than that.
I am not so sure about Baltar. How could he have survived the Nuclear attack? I seem to remember 6 telling him to Duck, but that cant have been enough. The point 6 is making is that he is the father of a half human half cylon, and therefore Baltar cannot be a cylon himself. (or is that the baby from Helo-Boomer)
as for any other conjectures – I bet nobody predicted what would have happened at the end of Season 1, now that we know what the Cylon “Plan” is, whats the chances of figuring out what happens next.