After Tetra and the King of Red Lions were announced as the new playable characters for Hyrule Warriors on the 3DS, it was teased that even more The Legend of Zelda characters would make the roster. As might have been expected, Toon Link has been confirmed as playable by Famitsu magazine. While he will not be included in the Legends mode (the story campaign), he can be used in any other mode.
Given that this particular iteration of Link has appeared in more Zelda titles, Toon Link will likely have a variety of moves that pull from a good number of those properties. There is a chance we will see a callback to Four Swords or Spirit Tracks. It is hard not to speculate. He is also doubtlessly one of many more characters that will be revealed in the near future. There is even a mention of the Helmaroc King making an appearance, probably as a boss.
Hyrule Warriors Legends is scheduled for an early 2016 release.
Source: Nintendo Everything, Esuteru