Vampires and zombies, I'm not sure of as they are essentially dead. Plus, not sure about vampires, but zombies would have the exact same DNA as the person they used to be so if anything you'd probably just morph into the living person - remember, absorbing DNA doesn't absorb injuries so you diffinitly wouldn't be able to morph a zombie and even a vampire I find iffy.
A werewolf however could be possible as that is an entirely different, living, creature that the person changes into. I'd say 'Nay' on Vampire and Zombie but 'Yay' on Werewolf. But that's just my personal belief.