My first thought on the top shot is "King Kong meets Frog," which isn't exactly what you're going for I'd imagine.
The sloth likeness is really a bit much. I love the concept, but I'm not sure how well it'll do in practice. It needs more reference to the original Poseidon I think. A more defined "head," fatter arms, a more defined (and less leg-like) engine assembly. As it stands, the skinny arms and little claws look too animal-like without getting enough practical function out of them. The Poseidon, for example has some kind of (magnetic?) locking mechanism on the ends of its arms, which lock in with the sides of the contianer that it picks up. Something like that would make this thing look much better. Save the claws for manipulator arms on a drone of some kind; they're pretty good but completely out of place on a freighter.