NEW YORK — Perhaps the toughest part of doing a biopic is getting a lead who matches the subject. With biopics on Orson Welles, James Dean, Bobby Darin and Andy Kaufman being prepped, interesting choices are materializing for the leads.Stars are ready to take part in “RKO 281,” which Ridley Scott is developing as a directing project at his Scott Free Prods. The film focuses on the feud between Orson Welles and William Randolph Hearst over the making of “Citizen Kane.” Though the project hasn’t been firmly set up at Disney, rumors are that Scott has talked to Marlon Brando to play Hearst, Edward Norton to play Welles, and Madonna to play Hearst’s mistress, Marion Davies. Other roles include screenwriter Herman Mankiewicz and rival gossips Hedda Hopper and Louella Parsons. Other major names are surfacing for various roles, though Scott hasn’t even deemed it his next project. Dean dilemma Director Marc Rocco, producer Marvin Worth and Warner Bros. have zeroed in on their top choice to play James Dean: Sources say it’s Stephen Dorff. The part has attracted young hunks since Leonardo DiCaprio dropped out along with director Michael Mann over two years ago. Though Rocco’s now busy doing a Janis Joplin pic with Melissa Etheridge, he confirmed he and producer Worth are eyeing Dorff. Director Barry Levinson is expecting to start production this year on his Darin biopic “Dreamer,” and his dream is to have Johnny Depp play the singer best known for “Mack the Knife.” They’ve had several meetings, and Levinson’s also sweet on Drew Barrymore to play Sandra Dee. Depp’s been heavy into biographies of late, playing director Ed Wood in pic of the same name and FBI agent Joe Pistone in “Donnie Brasco”; he’s about to play gonzo journalist Hunter Thompson in the screen version of Thompson’s drug-fueled travelogue “Fear and Loathing in Las Vegas.” Kaufman question Universal and Jersey Films’ biopic of quirky comic Andy Kaufman is shaping up to be a reunion of last year’s bio “The People vs. Larry Flynt.” Scott Alexander and Larry Karaszewski are working on the script, hoping to land director Milos Forman. And the actor most mentioned? “Flynt” co-star Norton, who might have finished playing Welles by the time the Kaufman project goes before the cameras. No Kaufman cast is set, with the exception of one player: Jersey’s Danny DeVito has agreed to play Kaufman’s manager George Shapiro.