I finally get to start posting about something fantasy!

So, my world does not yet have a name (and I'd like it to, for various reasons) but the main interesting thing about it is the Controllers, so that's what I'm calling this thread.
This world is for a treatment that I'm writing for the SAICFF treatment competition. (for those who don't know, a treatment is a three-page synopsis of a screenplay) So I don't need all the details just yet, not as many as I will need when I go to write the actual screenplay. But I need it to be original and interesting, so you awesome peoples can tell me if it is either of those things.
I'm not going to talk about the story here. Just the world.
So, it's a very small world -- probably only a few hundred people inhabit it. There is little or no formal government, instead the Controllers keep an eye on things (or are supposed to).
The Controllers are a group of seven people who have been given the power to control the different elements of the world. They are responsible for keeping things in the world running smoothly. When a Controller dies, his/her power is passed on to someone else (I've yet to figure out the logic of how the control is passed).
A woman can only become a controller if her father or husband is one. If two controllers have children, their children are more prone than usual people to receive the power.
Legend says that someday the seven controllers will come together in a particular sanctuary, and there their powers will converge and be released. Some Controllers want this, others do not. No one knows if the legend is true or not.
The seven controllers, at the time of this story, are:
Creature. Creature is the oldest of the controllers, over seventy years old. He controls all animals on the planet. Since he's very old and it's hard for him to travel, he'll be traveling separately from the others for most of the story, on some gentle animal I imagine.
Light. Light is a forty-something, gentle, wise man. He's the mentor type, and will be protecting the protagonist and will be her voice of reason. He's understanding and kind. He controls all light.
Water. Water is Light's daughter. She is early twenties, a gloomy and morose personality-type, which is compounded by bitterness over the death of her mother years before. She controls all aspects of water, and tends to keep things cloudy when she can, making the world often rather dark. The darker her mood, the thicker the clouds. She travels with her father.
Wind. Wind is Light's son, Water's brother, around nineteen. He controls the wind, and is intelligent, strong, and clever. After his mother died, he grew frustrated and started seeking ways to gain the power of the other Controllers. He uses his power to make it hard on those who oppose him.
Mineral. Mineral is Wind's friend, a serious, pragmatic, calm twenty-something. He follows Wind in his crusade, and also uses his power to make things difficult for the group who's trying to set things right. He has the power to do anything with rock and earth.
Plant. The previous Plant was Light's wife, the mother of Water and Wind. After she died, the power passed to a young farmers' wife. The new Plant is shy and has no interest in using the control. She can control plants any way she likes, but because of her timidity and lack of interest, the plants in the world are dying. Neither Light and his party nor Wind and his know who the Plant Controller is.
Heat. Heat is a sturdy, sensible, stern farmer who has no interest in using his power. He is Plant's husband, and the world is cold because of his disinterest and apathy.
That's mostly what I have so far.

I've done brainstorming about the story some... and I'm trying to figure out what kind of animals and plants the world will have. I'm leaning towards having things similar to our world (same classes and all) but have the species be different. But I haven't settle on it yet.
Any and all thoughts and suggestions are very welcome.
