[dahak]

Originally Posted by Etheral

Oh yea, I discussed this earlier but no definitive, can she do mythical animals?

There is some evidence that the siblings usual form types are more a matter of custom and preference rather than limits. Much how while Grey and Leon use different subsets of Ul's Ice Maker, they are capable of going beyond them.

As examples back during the Miss Fairy Tail competition Mirajane changed her head into Happy's and Gajeel's for example. Earlier she turned into Lucy as a decoy during Phantom's attack

And

Spoiler for One of the few remaining unanimated side stories [Fairy Tail Special 02]:

In Mirajane's Transformation Lesson she does a perfect Erza impersonation including armour and voice. She also shifts into a Fox, a Parrot, a Fish and Lucy in a swimsuit. She teaches Natsu how to shapeshift into Lucy's form but he can't manage her clothes. Happy only managed to turn his head into a copy of Lucy's but with cat ears and Lucy couldn't pick up the transformation at all, possibly because she was trying to stop Natsu from undressing to look at his copy of her breasts.

Note that this was set a couple of months before the S class tests.