By the official timelines and by events taking place across the series which are accepted by the creators of Zelda to have actually happened, for instance. In the Wind Waker there is a big statue of Link: the hero of time, inside Hyrule Castle which blocks the secret entrance. That statue is...
No it should not have a female Link. If there is going to be a playable female character it should be someone who is part of the story as well as Link who is a male. This way no matter who you choose to play as the game is completely canon, with both characters actually existing and playing...