To paraphrase George Orwell, all Oscar races are equally hard, but some are harder than others. The one facing the team of production designer Sarah Greenwood and set decorator Katie Spencer may be the hardest of all, for one simple reason: Not only are they facing stiff competition from the teams behind “Blade Runner 2049,” “The Shape of Water” and “Dunkirk,” but they’re also competing against themselves, since they’re nominated for both “Darkest Hour” (also featured here in Directors Chair) and “Beauty and the Beast.”