Daily Yo-kai Watch Factsさんのイラストまとめ

Koalanyan can be seen looking at a mural of a whale on his Bronze Treasure Medal. This is a reference to the flying whale from Yo-kai Watch the Movie: A Whale of Two Worlds.

Despite having no relation to him in any other media, Yellskitchen and The Woebra are two of The Ghoulfather's henchmen in Volume 13 of the Yo-kai Watch manga.

Youen Juushinka Kyubi-kun is the only instance where Kyubi's human form is befriendable.

Shirokumanyan is based off of one of Kagoshima prefecture's delicacies, which is also called the shirokuma. It is shaved ice with fruits such as raisins and cherries on top. It is also worth noting that shirokuma also means "polar bear", hence the costume Shirokumanyan wears.

Rongo Swirll's name is based off of Ringo Starr, a former drummer for the famous English rock band, the Beatles.

Hovernyan, Shoto Todoroki (My Hero Academia), Eren Jaeger (Attack on Titan), and Koichi Hirose (JoJo's Bizarre Adventure), all share the same Japanese voice actor, Yuki Kaji.

Lord Enma was created through the fusion of Alistair (top right) and Shien (bottom right).

Directator, despite having a physical medal, tribe, and semi prominent role in the anime for a small while, has never been befriendable in game and thus his rank is unknown.

So-Sorree is based off of Ittan-Momen, a real life youkai from Japanese folklore.