Ataru Cagiva's Legend of Zelda: Triforce of the Gods manga published between 1995-1996, 2 years before the release of Ocarina of Time in 1998, has the Link from ALttP meeting his ancestor who wielded the Master Sword during the Imprisoning War and lost against Ganon.
http://historyofhyrule.com/publications/manga_lttp3/015.html
The adult ending of Ocarina of Time seemed to lend itself to leading into ALttP with Ganondorf being sealed away by the 7 Sages, whose names were then passed down to become the names of towns in Zelda II: The Adventure of Link, and Link conveniently disappears from that timeline and wouldn't be around to be recorded as a hero. Ganondorf ends with threatening to exterminate the descendants of the Sages, Link, and Zelda, the the OoT team gave him a pig form at the end as special recognition to A Link to the Past and admitted they were dealing with the Imprisoing War of the 7 Sages.
The only exception is that Ganondorf was sealed away with the Triforce of Power, but that could have left things open or have been cleaned up. The child timeline could have been a new start leading into the Zelda Space World 2000 demo, while the adult originally connected to the older games they purposely referenced.
2011
http://iwataasks.nintendo.com/interviews/#/3ds/zelda-ocarina-of-time/4/2
1998
http://www.angelfire.com/games5/makzelda/interviews/kiootcomments.html
http://www.glitterberri.com/ocarina-of-time/1101-interviews/parts-they-want-you-to-see/
I think what happened is you had Yoshiaki Koizumi writing the manual and backstories for A Link to the Past and Link's Awakening, and then working as a director as one of the 3 original staff to begin the Zelda 64 project along with Script Director Toru Osawa (the creator of Kid Icarus). Koizumi created the backstory of the 3 goddesses in ALttP and continued working on the series with a lot of continuity.
http://www.wired.com/2007/12/interview-super/
Koizumi was pulled off a project to co-direct Majora's Mask with Eiji Aonuma, which was a side story sequel to OoT's child timeline ending. After Majora's Mask, Eiji Aonuma became producer of the Zelda series while Yoshiaki Koizumi became producer of the Mario series (previously the assistant director of Super Mario 64), and worked on Super Mario Sunshine.
The Space World 2000 demo of the realistic Link and Ganondorf facing off with sword fighting was what they were working on at one time for Zelda, a more detailed version of Ocarina of Time. But it was not the kind of game Aonuma wanted to make so they went in an entirely different direction with The Wind Waker, with Aonuma drawing from his childhood cartoons. Shigeru Miyamoto wasn't staisfied with a more realistic direction with Link having ear piercings for Zelda, and wasn't sure of the cartoonish direction either but approved the change.
http://shmuplations.com/miyamotoxnaka/
https://youtu.be/eEF9Utdu-L0
Yoshiaki Koizumi who had consistently worked on the Zelda series and its story with A Link to the Past, Link's Awakening, Ocarina of Time, and Majora's Mask, only lended a hand to the scenarios for Windfall Island in The Wind Waker before going off to be the producer of the Mario series at EAD Tokyo,. Eiji Aonuma as producer of the Zelda series took it into a new direction, and they branched off from Ocarina of Time in a new direction.
The timeline split from Ocarina of Time is similar to Dragon Ball Z and the time travel of future Trunks' story
- Trunks comes from a ruined future to warn Goku and the Z fighters about the Androids
- Trunks returns to the future, defeats the Androids, but is defeated by Cell. Cell uses his Time Machine to travel to the past and obtain the Androids of the past.
- While in the past Trunks encounters his Time Machine that cell used, altering his events. Trunks becomes stronger, returns to the future, defeats the Androids of his time, and is ready for Cell, and defeats him.
3 timelines
- Trunks returns to his future and dies against Cell
- Trunks returns to his future and defeats Cell
- Goku and the Z fighters defeat Cell live and a new timeline and future is created