I also like that the creators of the series are keeping some actors from the first season but giving them different roles. A few more seasons need to occur before we can see if this will continue, but i'm getting an almost theater troupe vibe from the idea, and for television it's an idea that could really pay off.
Below is a list of who's playing what, and this information is thanks to Arrow in the Head. I've provided the link at the bottom if you want to read the full article.
“Jessica Lange plays Sister Jude, a nun who's more sadistic than saintly.
Zachary Quinto plays Dr. Thredson, a psychiatrist whose forward-thinking ways conflict with Sister Jude's management style.
Chloe Sevigny plays Shelley, a nymphomaniac inmate.
James Cromwell plays Dr. Arden; EW says the not-so-good doctor is behind one of the season's newest frights: the Raspers. The mutated humans lurk in the forest outside of the institution and are a product of
experiments on Briarcliff's inmates. Oh, and Arden may or may not be a Nazi. Yikes!
Lily Rabe plays Sister Eunice, the Lange character's second-in-command.
Joseph Fiennes plays Monsignor Timothy O'Hara, Sister Jude's superior who finds himself on the receiving end of the nun's affections (and fantasies), but he's not entirely innocent.
Maroon 5 frontman Adam Levine plays Leo, one half of a newlywed couple visiting modern-day Briarcliff.
Jenna Dewan plays the second half of Asylum's high-profile newlywed couple.
Evan Peters, who portrayed season one's obnoxious villain Tate, is Kit, one of the newest Briarcliff inmates. Kit is committed after being accused of murdering his wife (played by Britne Olford), though he claims she was abducted — and not by humans.
Sarah Paulson plays a journalist named Lana who is committed to the asylum by her own girlfriend after she nearly exposes Briarcliff's darkest secrets.” (go to Arrow in the Head for full Article)