I think Xous' 2nd route is the one that will happen.
Btw, about that God Stone. Why is it "God"? Reshiram and Zekrom's stones are called "Light" and "DarK". But this one is called "God". I think that theory that Kyurem was the single dragon that split into Reshiram and Zekrom is very believable. Maybe, that single dragon was a god-like creature, hence the stone is called "God". And when it "split" (I don't think it was its body that split), it became weak. Also, black + white = gray, reshiram is white, zekrom is black, kyurem is gray - I can't be more obvious... Maybe in the 3rd, Kyurem will steal energy or whatever from reshiram and zekrom to gain power and recover its original look. And it will rule over Reshiram and Zekrom since it is the original being, the "God"... I don't know... It's just an ideia...
Btw, about that God Stone. Why is it "God"? Reshiram and Zekrom's stones are called "Light" and "DarK". But this one is called "God". I think that theory that Kyurem was the single dragon that split into Reshiram and Zekrom is very believable. Maybe, that single dragon was a god-like creature, hence the stone is called "God". And when it "split" (I don't think it was its body that split), it became weak. Also, black + white = gray, reshiram is white, zekrom is black, kyurem is gray - I can't be more obvious... Maybe in the 3rd, Kyurem will steal energy or whatever from reshiram and zekrom to gain power and recover its original look. And it will rule over Reshiram and Zekrom since it is the original being, the "God"... I don't know... It's just an ideia...