Once again I like the basic composition, and think it's a good idea for a poster, but the execution is lacking because they are obviously photoshopped in in a bunch of poses that clearly weren't shot with this particular poster concept in mind.
These do all seem to be the product of an actual promotional photoshoot. You can tell because the photographer clearly told them all to cheat their faces forward to make them look bigger, which presumabley they would not all be doing throughout the movie and which does lend itself to an "everyone's looking down" composition like this.