If You want any variable to become global, there must always be superior structure for holding data throughout whole project. So either your creation and selection scene have to be child of one menager node, or You should use singleton ( Autoload ) which will collect data from whole scene.
Whatever You will choose, generally You will have to create some dictionary with characters stats and features while in creator scene, and when it is done You will pass this dictionary higher (to parent or autoload), close creation scene, and on character selection screens ready() dictionary will be fetched from above again and visually recreated.