Yeah, honestly I think the potential Xion silhouette is the only major thing that dissapointed me from this trailer. I've personally always failed to see the purpose or appeal of the idea (if a good one truly exist). I said this back when we all thought Riku was Xion, but having her be norted in particular is just a retread in many ways of her previously established story arc. I struggle to see it adding anything substantial for her character, and unlike Aqua, Xion doesn't have any potential in-character reason to go against her friends (at least none that I can see). Anyway, I won't speak further on that.
In regards to the OP, if I'm simply being critical, I'd put my money on her(Xion) being the one all the way to the right. I can't really see it as anyone else at this point. The two middle ones are Ansem and Xemnas (left to right), and the fourth to the left is probably Data/Replica Riku. I say that last one because if we look at Data Riku when he wears the hood in recoded, it's top is noticably more circular than anyone else who's previously worn the coat. Vanitas would be the short, slightly more bulky one (probably cause of his body suit and mask that we consistently see him wearing) next to him, and Larxene would be the tall femanine one over to the right. Other than those, I really can't say. They all just sorta seem too similar for me to confidently guess.