water starter evolves into a quadruped, gains a beard, and has a weird sword horn. remains pure water type.
grass starter evolves into an anthro owl archer with a hood. uses its hood strings like a bow. becomes grass/ghost.
fire starter evolves into some kind of badger thing with an explosion coming out of its neck. looking into the game, it appears to have the same stats as charizard, but i'm assuming this is just placeholder. remains pure fire.
"Arceus" has the ability to become any type in the game by holding weird plate things. It's appearance also changes depending on what plate it's holding. The type of it's signature move also changes.
"Shaymin" as it's called has the ability to switch formes depending on weather or not it has a certain flower. Apparently it's stats also change.