Ngl these designs were a fun challenge. I have the other flowers sketched out but I wanted to do Pink first since I thought of a funny premise for how they all could exist together in the au.
So, you know how really popular characters will get like... Themed figures/statues for a specific line or what have you? Think Miku, MLP Characters, or Rem from Re: Zero. I was thinking that Asgore has been collecting these figures in his own time after Alphys gets him the original Mew Mew figure. It's one of those things keeping him afloat after his divorce, y'know?
Some of these are secondhand, others are bought as soon as they dropped, but he has this little collection of them in the shop/displayed on his truck. Honestly after this chapter, I think he identifies with Mew Mew's struggles of balancing work and her personal life to act as a force of justice, especially when her story takes the darker tone in Mew Mew Kissy Cutie 2 (which he's confirmed to enjoy in Chapter 2).
Anyway, to fit the monster-of-the-week format, the irritable ghost is trying out different bodies to see which one she likes best. She's drawn to Mew Mew in concept, but now she has different aesthetics to chose from. I imagine she mirrors each form she takes but palette swapped with her thicker eyebrows/more varied expressions as she does in game. You can imagine it.
The thing is that she only reaches a sense of reconciliation with the original Mew Mew body, like in the canon game. Certain figures choose to remain in their Dark World instead of leaving for Castletown, since they lack the same bond between body/spirit and want to remain with their respective Oranges. The irritable ghost is more antagonistic to start, similar to Undertale, because she's earlier in her transition and feels even more vulnerable than how we see in game. She's kind of a beloved antagonistic figure who eventually finds the right body for her and joins Castletown proper.
As for the specific fates of each:
Mimi Gladiolus, or Retro Dark World Pink, chooses to remain in her Dark World. She's modeled after 1960s magical girls, mainly Sally the Witch, but with some notes of Atsuko from Himitsu no Akko-chan and Princess Sapphire from Princess Knight. Because of her more innocent appearance and character, she and the irritable ghost clash the hardest when communication breaks down between them because Mimi wants to befriend the Fun Gang and is very childish. She is too attached to her found family to leave them behind, especially when The Roaring is explained to her. I imagine her reckoning with this decision is very Madoka-coded, where she sacrifices her freedom of being her own person to protect the wider world outside of Flower King. This figure is Asgore's favorite of his extended collection.
Polk, or Pulp Dark World Pink, also chooses to remain in her Dark World. She's basically a flapper magical girl, Betty Boop by way of Sailor Moon. Things go awry between her and the irritable ghost because Polk is way more confident and grounded than the irritable ghost. Polk isn't a femme fatale, but she knows what she wants and how to get it, which I think would clash with the ghost's aversion to dating/physical intimacy hardcore. Her choosing to stay behind in her Dark World is framed like a tragic, noir breakup-- The irritable ghost was a sudden apparition in Polk's life that gave her a thrill and new meaning, but doesn't recognize Polk as her own person in the grand scheme of things. Polk wants to live life on her terms, without anybody controlling what she does or feels, even if they love her. It's a whole thing, a 'We'll always have Paris' type beat.
Primalkin, or SFX Dark World Pink, goes to Castletown on being defeated. I imagine she's animated with stop motion and moves like a Rankin-Bass character-- Her design takes after high femme '80s icon, mainly Madonna and Cyndi Lauper. She's meant to give 'transfem fairy godmother' energy. I imagine that after failing to find a bond with Mimi and Polk, engaging in the swinging pendulum of trying different people to find who fits her values/lifestyle, Prim and the irritable ghost hold out the longest because Prim is confident, but flexible and less attached to the world, open to things being more than they seem. The thing that breaks them down is that the irritable ghost is still too guarded/self-hating, even with Prim being compatible, and Prim is in no mood to 'fix' the irritable ghost after doing her best to accommodate and encourage her. Their separation is the most amicable but bittersweet, like waking up from Wonderland-- The irritable ghost completes her arc with original Pink in the final encounter, but she's primed for the emotional realization by having Prim break up with her.