Well, there's already wyverns, who call themselves dragons due to a lack of dragons, so, lol. Either way, they'd most likely be demonic. Vampires, werewolves, and undead (other than ghosts) aren't available in the RP, and will not be accepted as a new species by me. There IS a sort of purgatory dimension, where ghosts exist, so... if we allow an undead, it would most likely exist there.

As for Sumable, given their resemblance to humans, elementals would most likely be 'Earthly'. The usage of certain elements shouldn't be a problem when trying to make a new species... just note that Ether can't be resisted, and lightning is rare.