Scion of an achievement-oriented Baton Rouge clan with roots in southern black aristocracy, toothsome, energetic leading lady Lynn Whitfield first watched the likes of Audrey Hepburn in "Breakfast at Tiffany's" and Bette Davis in "All About Eve" from the vantage of her grandmother's lap, attired in mink-trimmed frocks and seeing no reason she could not some day play those same types of roles. After gaining attention on the stage as one of the young women of color who people Ntozake Shange's poetic panorama of the black female experience, "For Colored Girls Who Have Considered Suicide/When the