I've given this a little more thought... And I'm starting to see a way the Shade could be Link without having to have been lost in the forest. So let's say Link finally does make it out of the woods, marries and has kids (possibly founding Ordon with Malon in the process), maybe continues fighting a bit, lives out his life and dies a peaceful death. Like The Janitor suggested, his kid(s) will obviously grow up hearing about how their dad was the chosen hero, the one who prevented Hyrule's Great Cataclysm by warning the Royal Family of Ganondorf's oncoming invasion and his own tales about traveling to Termina and his ensuing adventures there. Keep in mind, this is a time of peace. The Imprisoning War isn't happening on the Child Timeline, maybe a few monsters here and there or lingering followers of Ganondorf he'd have to take care of. Not exactly "the chosen hero" criteria for fighting. So Link wouldn't need to bother teaching his children the "serious" way of the sword, attacks that they would need when defending Hyrule and themselves when on the brink of war. But nobody ever saw Hyrule ever returning to a time of battle anytime soon, and so the child(ren) of the Hero of Time are not prepared for what may be coming when Ganondorf returns from the Twilight Realm. Link (HoT) sees this, and thus his spirit manifests into a ghost (Stalfos, whatever) of his former self, scarred with the wounds of fighting (The Shade is missing an eye) and not able to "cross over" as he knows his son (Link of TP) is not ready for what he'll have to face as the wielder of the Triforce of Courage. So, as the distressed spirit the Shade, he teaches Link his own ways of the sword for the battles that lie ahead, using the Gossip/Wind Stones that he used as the Hero of Time himself during his missions in future Hyrule and Termina.

Keep in mind I'm not just using the "go and do not falter my child" line as a basis for this. You also have to keep in mind that most of the Wind Stone songs are those from OoT and MM, the Golden Wolf possibly shows another connection between the Shade and Link, considering when Link is in the Twilight world, he takes the form of a dreary gray wolf (Like the Twilight.) When the Shade is in the World of Light, basically the entire mortal world, he takes the form of a golden wolf (Like light!) See how the different wolf forms of the different Links would correspond to which realm they're in? Why is it the Shade also takes the form of a wolf when he changes realms, just like Link does, but this only happens to the two of them?