I think one of the reasons I loved Newt so much in the Maze Runner book was because I knew he was going to be played by Jojen, or as I like to call him, the adorable kid who plays the drums and is Liam Neeson's son in Love Actually...
Also, in the second film, Aiden Gillen/Littlefinger is going to be Rat-Man - I've only just started book 2 so I don't know who he is yet, but my friend says he's perfect for the role... so chances are, Rat-Man is a manipulative dick...