The first wave of Amiibo figurines will comprise Mario, Donkey Kong, Princess Peach, Yoshi, Link, Samus, Animal Crossing's Villager, Kirby, Fox McCloud, Pikachu, Marth, and the Wii Fit Trainer.
The fourth AnimalFigurine in The Frozen Wilds can be found while completing the Shaman's Path main quest, which is the first quest you receive in The Frozen Wilds.