Assuming Wood is out, I submit High School Musical's Lucas Grabeel (pictured) for consideration. He might be a bit too tall to pair with Fanning, but they could always have him stand/walk in a shallow hole/trench. (Really, he's not going to be onscreen that long for it to become a huge inconvenience.) To me, Grabeel's face is angelic, but also blank -- perfect for a character who is able to cut off all your senses and make you feel absolutely nothing. Together, he and Fanning (character gift: to bring the pain) would be appropriately off-putting. Plus, they'd look so cute together.
Who's your pick for Alec? And are you hoping Fanning's meeting with Weitz goes well?