We know that different people playing different songs at different points do different things, not sure it's inconsistent.
TotK Zelda turns the Secret Stone into the Secret Stone of Time and Zelda into the Sage of Time. If the Sage of Time is some universal sage, she's the Sage of Time in OoT...
Huh?
Ocarina can do time travel: true.
The ocarina can send itself back in time: true.
Link having the Ocarina of Time allows him to de-age: not confirmed.
The Ocarina uses Timeshift stone magic: true insofar as it uses time travel magic.
The Ocarina uses Wind magic: true insofar as it...
It is the Ocarina that causes the time travel, and it can cause itself to de-age and travel back in time. I would actually argue it is Link's possession of the Ocarina of Time that allows him to de-age himself throughout the game: it is the most concentrated form of Timeshift power and Wind...