I've got a few more Alolan forms planned, though right now I'm sticking with Gen I pokémon (and their evolved forms from other generations) since that's what they're doing in Sun & Moon. This one may seem weird, but it'll make more sense in time ;P
Mime Jr. came to the Alola when people from Kalos and Sinnoh moved to towns near active volcanoes. Following its instincts to mimc anyone or anything around it, this pokémon started copying dance moves from rock and roll musicians and soon became extremely fixated by it. Eventually, the Mime Pokémon took everything it learned from other musicians, and developed its own dance style that it's extremely passionate about. People say that Mime Jr. took on this new form to the hot climates and the fiery passion in its heart.
Alolan Mime Jr. are often seen performing its own dance routine consisting of pelvic thrusts, wiggling its legs, and spinning its arms like a windmill. People and pokémon are often so fascinated by Alolan Mime Jr.'s dancing that they easily drawn to dance with it. The fire on top of its will only go out when it enters an emotional slump, only for it light back up once it gets its passion back. This pokémon's body also developed scarf-like appendages to help keep it balanced while dancing.