I think that may be over thinking it. LE doesn't seem misleading to me or trying to bluff-trap.
As I filtered the images of his face, I think I could make out his teeth, and a one sided grimace, that kind of scrunched up his nose on one side. His chin, caught a lot of light, and his whiskers, blemishes seemed apparent, creases around his lips. Since he's a murderer, I imagine whomever looks into that face and has an inkling it's Abby and Libby's killer may be very scared or in denial still. The sketch makes him look poker faced, but the grimacing creep on the bridge looks scary to me in the caps from Feb., as I review.
The sketch rendered from the eyewitness who according to LE saw him face to face makes sense to me, the expression, the features. He is somebody who can display grimacing rage, kill and then seem non offensive almost soft looking.