Sorry rose but have to disagree with most of these for a movie (but I can't disagree with how you see them in your head ~_~)
I'll explain.
Karl Urban as Kincaid- no explanation here, I just don't see him as Kincaid.
Justin Hartley as Thomas- I don't know who he is.
Viggo as Michael - Good choice, Sean Bean would be another
Meg Ryan (48) as Murphy - I loved Meg Ryan when I was growing up. Michelle Pfeiffer, Kathy Ireland, etc. These were my generation of celebrity females. But Meg is little old now to be Murphy. And Meg didn't age well either.
Meryl Streep (60) as Charity - too old, and can you picture Meryl as the wife of Viggo.....uhhhh no.
Kate Bosworth as Molly - Kate is pretty, I am not too sure about her as Molly though.
Catherine Zeta Jones (40) as Susan - a little older than I would picture Susan, Jones would make a good Arianna Ortega
Keep in mind is easier to make someone look older than it is to make someone look younger.
"Karl Urban as Kincaid- no explanation here, I just don't see him as Kincaid."
OK...before Urban got the role of Dr. McCoy, he had another thing in common with the late DeForest Kelley; both were routinely typecast as bad guys.
Urban as Kincaid, maybe...Warden Morgan, definitely