According to one poster on FSM, James Newton Howard was brought in to work on Exodus: Gods and Kings. So does that mean Iglesias is off the project? That would have been not good. Howard can do a great job, don't get me wrong.
Anyway, someone needs to confirm this. For now, it's just a rumour.
Weaver gives an Oscar worthy performance in the 86 film.
What I like about her in all the films (yes, all four) is that she really grows and changes. It's not like Ripley is the same character in each film. And it is also because of her that I can't ever really hate any of those.