Also, apparently Xigbar at one point sees an image of Ven in place of Xion.
I don't know how that works out.
Probably the same way that Roxas sees Xion with her hood down and Axel sees her with it up on Day 74.
It also might have something to do with the extended Deep Dive scene we see between Xemnas and (supposedly) Roxas on Day 27.