Canadian-born sisters Nicole and Natalie Appleton know all about celebrity. As former members of Spice Girl wannabes All Saints, the Appletons saw their relationships with rock-star boyfriends (Nicole’s with Oasis’ Liam Gallagher, Natalie’s with Prodigy’s Liam Howlett) create enough jealousy to bring their pop group to a bitter end. Now the sisters are poised to have the spotlight all to themselves with their first solo outing. But despite the harder-edged first single, “Fantasy,” the album is more vacuous pop fluff.