Since I've seen a number of people ask, I'll just put this here. It's only tangentially related to Smash Bros., but I don't have an amiibo topic on the Breath of the Wild board.
I tested Young Link's Smash amiibo in Breath of the Wild. It drops a number of fish and a treasure chest. After a number of resets, all I could get out of the treasure chests were Royal Broadswords, Royal Claymores, Royal Halberds, and various elemental arrows.
This does not match the drop table of any other Link amiibo; only the Toon Links give fish, none of them give Royal Halberds, and none give both the Broadswords and Claymores. However, this isn't exactly generic functionality either -- non-Zelda amiibos don't give treasure chests.
Therefore, it's safe to say that it does not count as Majora's Mask Link, Ocarina of Time Link, or Smash Bros. Link in Breath of the Wild. And unless someone can prove otherwise, it looks like you can't get any amiibo-specific drops from it.
Creator of Jay's Journey, including Jay's Journey Reimagined/Jay's Journey 2: Worlds Apart! https://jaysjourney2016.wordpress.com/