I just squeed, those are fantastic! I really think the posters would look like that. Although, another likely one is some variation on the book cover for The Andalite's Gift, which is pretty movie poster in itself. I like the feet one best. Although, I think, that if a non-fan saw it they'd just think it was a blue goat and laugh at it, but we know the truth and that the creature is much more sinister. My only gripe about the foot one is that you can see they're symettrical and that they're slightly scuffed, I always imagined Andalites as being ridiculously well groomed. Minor stuff though, the concept is still too awesome.
Do you have a larger version of them posted anywhere? With your permission i'd love to use them as desktop backgrounds.