After earning Oscar nominations for their breakthrough film roles — Rooney Mara as the hardened sleuth Lisbeth Salander in “The Girl With the Dragon Tattoo” and Steve Carell channeling John du Pont in “Foxcatcher” — the two actors are back with very different performances. Mara is shy and subtle as a young woman in the 1950s who falls for Cate Blanchett’s lead character in “Carol.” And Carell is all manic energy and heart in “The Big Short,” which details the individuals who cashed in on the recent housing collapse.