Butterfield had been reported to be the favorite for the male lead. Sources now say he and Purnell have offers and negotiations are underway.
Burton will direct the pic, which is based on the Ransom Riggs novel about a teenager who finds himself transported to an island where he must help protect a group of orphans with special powers from creatures who are out to destroy them. Green would play the title character, who acts as a guardian for these orphans.
Chernin Entertainment is producing the pic.
The hope is to begin production in the first quarter of 2015.
Butterfield is repped CAA and was last seen in “Ender’s Game.”
Purnell, who is repped by WME and Curtis Brown, was most recently seen as teen Maleficent in “Maleficent” and can be seen next as young Jane in David Yates’ “Tarzan.”