I have source linked the original post and am only posting it like this so it is posted like a picture instead of as a photo in text. What follows is the wonderfully well thought out explanation from the original source as to why these would be Sailor Saturn’s team:
Rayquaza - Since Sailor Saturn is capable of destroying the friggin’ world with her Silence Glaive, I figured she was entitled to some Legendaries. I also wanted a serpent-like Pokémon to reference the ouroboros, the snake that devours its own tail, since Sailor Saturn is the Soldier of Death and Rebirth.
Audino - Since Hotaru has the ability to heal minor wounds. I imagine that this is her main Pokémon and she only has access to the others when she’s Sailor Saturn.
Kabutops - Since this Pokémon has scythes for hands I chose it to represent the Silence Glaive, which was once referred to as the “scythe of the Goddess of Death”. There is no way you can convince me that Sailor Saturn wasn’t based off of something Naoko Takeuchi saw on the cover of a death metal album.
Ho-oh - A phoenix Pokémon, another symbol of creation and destruction.
Registeel - I picked this one because Hotaru is a friggin’ cyborg in the manga, and also because Registeel represents the Iron Age of humankind, a period of time which propel humanity to great feats of creation and destruction.
Mewtwo - A Pokémon created as a weapon from the DNA of Mew, the Pokémon from which all other Pokémon were born. I gave Sailor Saturn the more destructive half of this pair because, y’know, world-destroying powers and all. Also, Mewtwo feels alone in the world and Hotaru is treated like an outcast by her peers, so that fits too.

