E3 2014

This is exactly the conclusion that my friend and I came to while talking about the footage and the quote. Demise's curse only dictates that his evil, those with the goddess bloodline and those with the spirit of the hero will be locked in an eternal battle. No where is it ever said that the Hero has to be male, or, furthermore, that the one who hails from the goddess' bloodline cannot also be the one with the spirit of the hero.

The triforce doesn't split randomly. It always goes to 3 people if someone with an imbalance of the 3 elements that make it up (power, wisdom, courage) is the first to touch it. It is also sentient as seen in the openings to oracle of ages/seasons and the end of LTTP where it speaks to link.

If an imbalanced person does manage to touch it first, they get to keep the piece that best suits that persons character, and the other two seek out people representing the remaining two elements, which are normally Zelda and Link. It's been shown multiple times that link would be able to touch the triforce and make a wish immediately because he has all 3 elements in balance (unlike Ganondorf), but he still only ever receives the one piece when it gets split. It's also seemingly transferable to someone else with similar traits (as seen in twilight princess when Zelda gives midna the triforce of wisdom).

So even if you did end up with someone who ended up both as zelda reincarnation and with the spirit of the hero, they'd still likely only receive one piece of the triforce with the other one ending up with someone else