I am not going to withdraw my support for Vivi... two Ds? So what? I mean, Blackbeard and Ace were on Whitebeard's crew. We have two AdvCoC users on the Strawhats. Heck, in the past, the idea of a Warlord joining them was thought impossible.
Besides, a line Vivi thought when she was captured intrigued me. "I might have to do something about this." What Vivi, what could you do against these CP-0 Agents? You were clearly thinking of something....
Also, her ancestor, Lili, pushed for the Dawn of the World. Her father is dead and Cobra made it clear that Alabasta was to stand with the D. Surely this adds credence rather than the opposite?