Personally, I don't see OoT being the first Zelda, because the creators of the game only named it as the first one when referencing TP and Windwaker, while the question of the Zelda games created prior to these three has never been completely resolved, or even addressed, by the current Zelda staff.
Also, it is kinda assumed that OoT gannon is TP gannon since OoT gannon was a theif and TP gannon was sentenced as such, but I never really recall him possessing the triforce in the child timeline, so it is up for debate. This is especially true because of the rules of triforce physics, which state that if Gannon from OoT had to steal the triforce (which he hadn't done in the proposed TP timeline to my knowledge), he could not be the gannon from TP, where triforce weilders are born with the triforce.
EDIT: you know, no one ever questions the Mario timeline.