The 'lucky ones' in 'We Were the Lucky Ones - A True Story' are probably the characters who managed to escape some sort of tragedy or misfortune. It could be that they survived a war, or perhaps they were able to overcome poverty or illness. Maybe they were a family that stayed together through tough times when many others were torn apart. It all depends on the context of the true story.
It could be that he was lucky enough to inherit some special power or ability that sets him apart from other vampires in the Argeneau world. This power might help him in various situations, like fighting off enemies or winning the heart of a special someone. Another possibility is that he was in the right place at the right time to avoid some great disaster that was about to befall the vampire community.
His best friend could be a main character. Maybe his friend is like a side - kick in the 'game' of his life, always there to help him with quests or give him advice that's like hints in a game.
The Christmas story in Luke tells of the birth of Jesus, including details like the angel's announcement to Mary and the shepherds visiting the newborn.