What if all the Shadow Links that the Hero of Hyrule has had to deal with over the generations are NOT simply magical clones created in the moment, but are in fact past incarnations of the Hero who have been waiting for the next Link to arrive so that they may test him? We know it's conceivable thanks to the mysterious swordsman spirit from Twilight Princess, but my main inspiration for this is actually Zelda 2. Consider this: the Triforce of Courage was sealed in the tomb of an ancient hero, and the final boss you need to defeat is not the guardian Thunderbird, but a Shadow Link (The original Shadow Link, no less). It's not too far a stretch to think that the tomb is that of a past incarnation of Link, and a bearer of the Triforce of Courage.