Why would they do that? Clearing up speculation one way or the other just spoils the surprise.

We're all just going to have to wait until a future Fan Fest to know for sure. If they announce two more Jobs, and neither are Dancers, then that's that.
If Dancer is a confirmed job, then we'll keep seeing speculation on if the girl in the trailer is one or not up until the point of her being a Monk is hammered in in the story.