Here are my designs for the penguins.
I like the penguin in the middle on the page below. I think it would work well in the animation
I like the design below. For the animating I would use the same model for both but with a few small changes to make one look less intelligent. This character idea does have a problem though, it may not look as good when it walks because of the body shape.
I would not use teeth though for the less intelligent one (below right) as penguins do not have them.
I would probably leave its tongue hanging out of its mouth instead.