General Zod turned out to be a rumor only. Lex is bound to be in the film if they're basing elements of the film from "Birthright". I wouldn't be surprised if we got some "Superman:Secret Origin" in there as well. Geoff Johns has a lot of pull with DC Ent right now.
Anne Hathaway was RUMORED to be up for Lois. Her casting in "The Dark Knight Rises" rules her out not. There hasn't been any formal actresses for the role announced yet. As I said Natalie Portman was offered a role but passed, I wouldn't put too much merit in this since she also passed on Alfronso Cuoran's "Gravity" around the same time. Rachel McAdams I wouldn't mind seeing as Lois. She looks like she could be great with Henry Cavil. Elizabeth Banks is another actress I mentioned before.
@ObiWanShinobi...Jon Hamm as Lex Luthor is my pick as well. I would have Lex though as a periphery character. In the background but his presence seen and perhaps felt still. The business mongrel of Metropolis who also has a degree in astrophysics and astronomy. This is how I would portray Lex. I would like to see Brainiac as well.