The entrance on Onigashima seems to take some reference from shrines devoted to
Inari Okami, japanese fox god who represents, agriculture, prosperity, entertainment, to name a few. Several shrines devoted to it have kitsune at the base of the entrance, similar to Onigashima.
The Fushimi Inari Taisha, head Shrine for Inari
The entrance for Onigashima makes sense, as it's a party full of life and fun, as well as lots of food.
Inari also has ties to manufacturing and swordsmiths. And we know one fox in Wano who loves to look after swords. Plus the manufacturing bit ties in with what Kaido and Orochi do for a living together, they work together to produce weapons for each other. The fire festival a celebration of their pact.