Actors to play in Host movie??

Hey, so if the Host were made into movie form, who do you think would be the best actors to play the characters? Here's my list:

Melanie/Wanda: Whoever gets this role will need to be able to play two very distinct roles, the docile Wanda and the fiery, hotheaded Melanie. She'd also need to look decent with a short haircut, since Wanda chops off Melanie's hair to piss her off in the book.

Melanie is described on page 13, "This face was a hard rectangle, the shape of the bones hard under the skin. In color it was a light golden brown. The hair was just a few shades darker than the skin, except where flaxen streaks lightened it, and it covered only the head and the odd fur stripes above the eyes. The circular irises in the white eyeballs were darker than the hair but, like the hair, flecked with light."

So she's lightly tanned, with streaked golden/brown hair and tawny eyes. I have to say I'd go with Rachael Leigh Cook for the part, I cant help but feel she fits it well in terms of looks. As for how she'd fare with the split persona--Only an audition could say for sure, I suppose. But she certainly looks like she could pull off both nice and nasty.

Wanda/Petals Open to the Moon: For Wanda's new body, at the end of the book, it describes a girl who looks younger than her years, and is childishly endearing, someone who looks at home in frills and ruffles.

"The skin on the face had the same silver undertone-silver like moonlight-as the hand did, with another handful o the golden freckles across the bridge of the nose. Wide grey eyes, the silver of the soul shimmering faintly behind the soft color, framed by tangled golden lashes. Pale pink lips, full and round, almost like a baby's. Small, even white teeth behind them. A dimple in the chin, And everywhere, everywhere, golden, waving hair that stood away from my face in a bright halo and fell below where the mirror showed."

She was also described to look somewhat like Melanie's body. I think I would go with Emily Jane Browning, from A Series of Unfortunate Events, seeing as she has a strange, etherial sort of look to her, and an agelessness that leaves one wondering if she's young or old. An old soul in a young body--perfect for Wanderer.

Jared: This one has me in a pickle. Jared will have to be able to act warm and lighthearted, for the flashbacks, and horribly, cruelly cold, for when he's around Wanda. He seems very affectionate/passionate/horny around Melanie, calling her 'baby' and such. Someone with light hair, tan skin, crinkly eyes. He's from Arizona and was raised in a very rural area, so probably a bit of a western twang/drawl to his voice. I'd honestly say that my closest image is Matthew McConaughey, but I'm afraid with an actress as young as Rachael Leigh Cook he might come off as too old. Although, with the end of the world as you know it, age might not mean as much.

Ian: Hands down, my vote is for Adrien Brody. I'm sure some might not agree with that choice, but his mild-manneredness, his calmness, and his deep, quiet love for Wanda brought his face to my mind the entire time I read the book. If you find him too old, or too homely, I suppose another actor I could see playing the role would be Matthew Macfadyen; he exhibited a great capacity for deepseated love in Pride and Prejudice, and I think displays just enough awkward lack of assurance. Or maybe even Hugh Jackman?

Jamie: Someone reaching that awkward puppy stage of puberty, all arms and legs and elbows, who would have familial features similar to Cook's. My first thought was Taylor Lautner, but since he's starring in Twilight I'm pretty sure Meyer wouldn't want to use him in another, unrelated film of hers. Any ideas?

And please, feel free to add thoughts as to who you think would be best for other roles as well, such as the Seeker, Ian's brother Kyle, Jeb, etc.