I think that Good Luck and Bad Luck is something you only recognise after the fact. You might think it is unlucky to be exiled from your Sartarite Tribe, but otherise you'd never have got to sail down Magasta's pool on a Giant Cradle with (an) Argrath... Or, you might think everything you touch turning to gold would be lucky - King Midas might disagree...
So a lucky character doesn't have to win every contest, but even losing will end up with some sort of positive outcome. (Joseph gets sold into slavery by his brothers, thrown in gaol by his new owner, and still ended up as Pharaoh's right hand man...