I think Link and Zelda are.... Um. Just... Avatars. And this little dude, according to artist's description, is called Daphnes, like the king from Wind Waker and Minish Cap.(I don't remember at all) So... According to Zelda's timeline (Skyward Sword, Minish Cap, Four Swords and finally, Ocarina of Time) probably the child is the king! (My english is a trash, sorry. Btw, awesome avatar, I love Rock!)