Terrence is still in his twenties in Brechalon and Henry Cavill would be a good choice to play him.  Of course I would want British actors for all these characters.

Emily Blunt would make a great Iolanthe.  She is beautiful but can be scary cold too.

I really like Charlie Cox in Stardust and he would make a great Augie.  I think though Augie would be the easiest character to cast.

Annabel Scholey might be a tad too sexy to be Yuah, but Yuah is described as being more beautiful that Iolanthe and there aren’t many actresses who would fit that bill.  I really liked Annabel in Being Human.

Zeah is probably the hardest character to cast, but I could imagine David Thewlis speaking his lines complete with stutter.  He’s actually the right age, though I think he might need make up to look a bit older.

Prisoner 89 aka Zurfina.  As soon as I saw Lynn Collins with blond hair (it’s usually dark brown) I thought she was perfect.  The fact that she is Dejah Thoris in the upcoming John Carter makes her a must for the part.

Andrew Garfield would make a great Nils Chapman.  In fact, I think he would make a better Nils Chapman than a Spiderman, but that’s just me.

Karl Drury is a scary guy and needs to be intimidating, especially to Nils.  Rufus Sewell could pull that off in spaces.

Have a different actor in mind?  Let me know.