Seems to me like they could put it in any branch. Although the adult timeline is the least likely to me, because the idea of Hyrule de-flooding sounds like a far-fetched explanation, and explaining why Sheika technology exists could be hard. I think it would be really easy to place this in the other timelines (although the downfall timeline would be easier because of Ganon being in this game when he died in Twilight Princess, and the resemblance to the mountains in Zelda 1.
Can't wait for The Zelder Scrolls 3: Breath of The Wild Hunt!







