GREAT BIG BEAUTIFUL LIFE, E. Henry (special edition)Alice Scott is an eternal optimist still dreaming of her big writing break. Hayden Anderson is a Pulitzer prize winning human thundercloud. And theyre both on balmy Little Crescent Island for the same reason: To write the biography of a woman no one has seen in years or at least to meet with the octogenarian who claims to be the Margaret Ives. Tragic heiress, former tabloid princess, and daughter of one of the most storied (and scandalous) families of