The Gold Kirby Team represent the Jiggy, a golden jigsaw puzzle piece which are found in groups in each level of the Banjo-Kazooie series.
The stage represents Glitter Gulch Mine, an underground mining level in Banjo-Tooie which features the Jiggy as a collectible goal item.
The music track represents the musical theme of Treasure Trove Cove, a seaside oceanic world in the Jiggy's debut game, Banjo-Kazooie.
The Gold Kirby's frequent jumping and battle conditions reference the collection of Jiggies in the Banjo-Kazooie series where they often appear jumping on-screen and will float in midair before being collected.
Other trivia:
This spirit's Support type references the Jiggies' role of aiding Banjo and Kazooie by collecting enough Jiggies to enter a new area.
This spirit's Lightweight ability further references how Jiggies float in midair before being collected.