It was a major plotline that the final five were a taboo among the cylons, but Baltar’s influence led to Deanna’s breaking the taboo and using unorthodox methods (suicide; consulting with the hybrid) to find out about them. They are still taboo - only Deanna is enamored of them.
Did anyone else think that both Sharons had created an elaborate ploy together? Helo-Sharon says she can’t trust humans and the baby must stay there, but Boomer-Sharon threatens the baby, making Six decide the baby must go back to the humans. I’m very surprised that Six left with H-Sharon though. I wonder if mental-Baltar will make another appearance?
It wasn’t clear until this episode that all of the Deannas were acting in accordance unlike Sharon, for which there were only one or two anomolous examples. There had been some discussion about possibly boxing Boomer, but I guess they decided not to since only one model really betrayed them, and the other one worked from the inside with caprica-six’s support.
I have no frakkin clue who the final five are supposed to be. Last season I thought they had implied that they were previously boxed cyclon models but it appears they have some other function.