I have ideas for the others, and an idea for Meta Twiknight's altered cutie mark.



Meta Twiknight: Her cutie mark has the Galaxia at the center, and surrounding it are the following: A stone (Rockity), a whip (Whippyjack), a warp star (Starkirby Glimmer, who I consider the Element of Justice after Starlight's reformation; you may not have to include the warp star), an easel (Pinkie Roller), a paint dish (Adeleine Dash), and an apple (Flutter Woods).



Whippyjack: Her cutie mark is a whip hitting an apple tree, and she wears a whip on her waist, as well as a cowboy hat with two stars on the sides.



Rockity: Her cutie mark represents her parents, being three red, stylized stones, and she wears Stone Kirby's hat from Kirby Super Star and its remake, except red, with a yellow ponytail, silver accents, and bronze star.



Moundo Flanks (Rockity's father): His cutie mark represents his family, being a red stylized stone on the bottom, and on the top, two brown stylized stones. He wears the same headband as Moundo, and his weapon is the Kirby Fighters Deluxe-only alternative Hammer.



Blocky Bits (Rockity's mother): Her cutie mark represents her family as well, being a red stylized stone on the bottom, and on the top, a brown stylized stone on the left, and a gray stylized stone on the right. She wears a crown made of stone, and her weapon is a stone mallet.



Starkirby Glimmer: Her cutie mark is a warp star leaving its trail, and she wears a peppermint-like headband to supercharger her magic. She also wears a pink long-sleeved shirt, a red belt and pink shorts with a hole cut so you can see her cutie mark, and red hoof-shoes on her hind hooves.