Character/story ideas

So I have this story which doesn't have a concrete plot yet. It contains a bunch of characters that are currently nameless. Basically the setup is that all of the characters are creatures from various mythologies. The characters live in fictional countries based off of the countries where each mythical creature originated. The problem, besides the lack of plot, is that I don't know enough about different mythological creatures. And that I don't know if I want it to be traditional fantasy, urban fantasy, or something else entirely.

Here are the characters that I might use:

• Three siblings (two sisters and a brother). None have names yet, and I haven't decided what creatures they should be. I'm thinking they'd be the main characters, but I don't have much beyond that.
• Some guy who has the dangerous job of taming basilisks for a living. Maybe he's an elf or something.
• I'd like to throw a kitsune in there. I'm picturing one as a prince or the son of someone held in high political regard. He'd be constantly running off and getting into trouble.
• A fairy, whom despite her young age, is a priestess. She is very powerful, but has no friends, and feels more like a tool than a living entity. One of her powers is that her soul can leave her body and possess the bodies of others. She uses this to subdue enemies and extract information from them. I want her to be named after a species of butterfly.
• A werewolf who is a renegade of some sort. He's vengeful and power-hungry. He's the leader of some kind of pack. I have no clue what to name him.

The only thing I can think of with the plot is that one of the three siblings (or someone close to them) has fallen ill from an incurable disease, and there is only one extraordinary way to save them (like the Fountain of Youth or something). The problem is that many people want this extraordinary thing, and the few that have any information on it are very tight-lipped.

OK, that's totally cliche.