Mr. Black is simply Mr. Black. Tusks is obviously the guy with the tusks (it's in the name). You see him lifting up someone by the throat in the trailer. And Flusher, Birdface, Optimus Prime, is indeed the one who was next to a rearing and roaring hound in the trailer.
Mr. Black is seen roaring up into the sky with what looks like Stan's spinal chord and skull in his hand in the trailer, for clarification.