Or a character completely unrelated to the BO. There is also the possibility that the eyes are just included in the promo to generate hype and get people talking, and it worked. Maybe there won't even be a character like that in the movie.
It does have to be said that this is a promo. The "real" trailer hasn't even came out yet, but I agree with this. I don't think there's any way that such a significant thing would be revealed in a movie promo, and I have my doubts on how Rum will "appear" in the movie to begin with.
However, I do think that the eyes are supposed to represent Rum, and they know people are going to draw the comparison. It's good marketing, and I'm sure they are going to pull out all the stops to try and make the movie as successful as possible.