Here’s a rundown
Hyrule Warriors supported amiibo on Wii U, so it stands to reason that the same would apply for the 3DS. This newest video confirms it, complete with footage of what the supported figures (Zelda, Toon Link, Link, Sheik, Ganondorf) actually do.
Basically, you’re getting new weapons and items, which aren’t as exciting for casual players, but will pay dividends for the hardcore fans who have 100+ hour save files. Oh, and the Wolf Link amiibo is supported too, as are “any” amiibo toys, which allow random unlocks.