Vulture reports that while Shailene Woodley ("The Descendants") has already passed, Dakota Fanning, Emily Browning ("Sleeping Beauty," "Sucker Punch"), Bella Heathcote ("Dark Shadows") and Lily Collins have all read for the role. However, it's reportedly Haley Bennett and Chloe we're-calling-her-Grace-now Moretz who are the "main contenders" for the part.
So essentially, it's one relative newcomer and one "veteran" (for lack of a better word). Bennet has had a smattering of roles, most recently in Gregg Araki's "Kaboom," but came on most people's radar when she was cast in Terrence Malick's "Lawless." Meanwhile, even at the tender age of fifteen, Moretz is a seasoned actress, making her name on "Kick-Ass" and since then lining up a variety of strong projects ("Let Me In," "Hugo," "Dark Shadows," a recurring role on "30 Rock") all the while showing that she is a talent to be reckoned with for years to come.
As for the fundamentalist home? Peirce has reportedly "approached" Jodie Foster and is "interested in" Julianne Moore, but those both seem pretty early in the game right now.
It will come down to a matter of vision and finances we guess. Do the producers go bravely with an unknown (who will be cheaper too) for the lead, more or less like Brian De Palma did the first time around with Sissy Spacek? Or do the filmmakers pay a bit more and bank on a name? Guess we'll soon see.