So with my thought on different yin-yang pairs that would cycle between 6/7 Miraculous, I also wanted to cover the different pairs for Felix and Marinette as I do think they are a pair that can easily use both Ladybug and Cat.
So I wanted to see if that could extend to my idea on other pairs, particularly Fox/Peafowl and Bee/Butterfly.
Which, for this, there are tweaked themes for these pairs.
Fox and Peafowl echo themes of Deception and Truth/Vision.
Bee and Butterfly echo themes of Order/Notion and Chaos/Emotion.
And a bonus, Turtle and Serpent, the neutral pair that undo wishes, and loosely echo space and time.
Initially, I'd say immediate stand out picks are Serpent!Marinette and Turtle!Felix.
As Wayzz and Koyll lightly echo space and time, you can see a bit of those themes echoed in Felix and Marinette.
Felix is a character who literally likes to have his space. He'd rather be withdrawn, in his own bubble, then have it be filled with others. He's a character that would rather open up his space on his terms, and let others in on his terms.
It's one of the big reasons Turtle is a natural, easy click, one of the archetypes I associate with turtles is being a loner, to be self-reliant, not make it through life on fellowship and trust. Felix, from what I've seen concept wise, is a loner.
Another factor is the probability is that Felix isn't a character that lives life in a rush. That he moves at his own pace and leisure. It could be a stretch and may be just my own interpretation, but it works off the fact that for the PV, one of the few things they show off about Felix is him spending time in a library, implying he likes to read and/or is quite studious. Typically those that spend their free time reading not only show off their dedication, but that they take time to enjoy/learn, and are fine chilling as they do so.
Him being a reader/scholar can also work off the themes of turtles being knowledgeable/wise, and books in media are heavily tied with intelligence.
Last detail I'll point out that matches Felix with Turtle is his defensiveness. At least PV wise, Felix who can be a mean/antagonistic character, isn't someone who goes out of their way to bully others. You have to come into his space and provoke him for him to snap back (like ignoring his clear no to romantic confessions).
Turtles are animals that can snap back and have a very nasty snap.
The thing is though, these animals aren't going to go out of their way to pick fights. They bite back when provoked, when space is invaded; otherwise, they'll leave or simply want to chill and be unnoticed and unbothered.
Of what I speculated from Felix, that's a pretty similar behavior.
And of course, I've mentioned it before, but I do think there's merit in a monochrome character getting something colorful to reflect a beneficial change in life, to gain color in life, something more lively. Turtle as a colorful Miraculous meets this quota, though I will be going over a few colors and what they can bring to Felix, as unfortunately for me, they had the black kwami have green eyes, suggesting green could be a color he could be associated with, but they also decided to do a green turtle. So I could have Cat more tied to chartreuse (to work off yellow popping up in Cat heroes) and Turtle is green, or have Cat be green and Turtle is more cyan/turquoise.
Green is a color tied to harmony, security, growth, and healing. It can have additional perks of generosity, hope, and prosperity, and negative themes of being envious, greedy, inexperienced, stagnant, and judgemental.
By the entirety of Felix, from PV to canon to fanon, there are aspects of the negative associations of green to be seen with his character, fans did have the idea of him being jealous of Adrien and canon backed it (in response to seeing Adrien having a lot of friends), PV wise he is a stagnant character that doesn't want to change, and being judgemental is a trait that just clicks with him. Green though can easily cover what he needs growth wise, to literally grow, have a sense of security which can be nice for a reluctant hero, and to learn to be generous and harmonious as a trade off to someone solitary and chaotically spiteful.
Now going off Turtle possibly being more cyan/turquoise, those colors come with calmness, clarity, communication, compassion, individuality, renewal, practicality, support, healing, enlightenment, peace, empathy, and stability. Negatively, they come with secrecy, narcissism, stress, and anxiety.
This is one of those where a lot clicks, but offers a lot growth wise, especially empathy and compassion. And can doubly work off what Turtle should factor in for users, not just providing self defending, but extending protection to others.
Now on the topic of kwami, I do see Felix and Wayzz getting along well. One of the things that stands out to me about Wayzz is him being adaptable. He's able to pick up on his human's personality and quirks, and he's able to adjust and take in what they're interested in, what they like, and how to work off of them. Which how, despite being with Nino for a very limited time, he's able to integrate himself into Nino's interests, greeting him as Nino likes.
As Felix (PV) is a character that was very reluctant to be a hero and have heroic responsibilities placed upon him, Wayzz would make that much easier, getting a quick idea on how to work off Felix and reason with him. Wayzz would validate Felix needing to self protect, to prioritize himself, but also ease things out to others. Secure stability to others, that they have rights to a safe space as well.
Now for Marinette and Serpent, this wound up to be another nice color coded pair with extra little themes to work off.
When I was doing Koyll's design, pink was one of the colors that stood out to me, and being made a counter to Wayzz and a sister of Sass, yeah it was an easy pick to contrast both of them. And her being a pink kwami with black details and blue eyes, it's very easy to work off Marinette's primary colors (only thing missing is white). What's the extra icing on this cake is the factor that Marinette is associated with plants, not just from the iconic blossom design she does, but also from her balcony garden, and in a few different mythology, there are serpents and dragons wrapped around the base of trees or associated with trees (Laden, Nidhogg, and Mucalinda). And Marinette's signature flower is a Chinese plum blossom, which comes from a tree.
With Koyll working off Ouroboros and time, Marinette can work off the concept of time very well.
Time is always in motion and never stops. Marinette is a character I perceive to be incredibly productive, a true busy body, always likes to be doing something, always compelled to meddle, just always be doing something. I really don't know if she truly knows how to stop and relax. Time is also something that extends and effects everyone, and that can work off Marinette being very sociable, and involving herself with everyone.
As for Marinette's potential ties to serpents and snakes, the biggest one to stand out is duality and healing.
Snakes/serpents have long been a dual symbol, a fine balance of themes, from life and death, creation and destruction, benevolence and malevolence.
Ouroboros even echoes yin-yang as it cycles between creation and destruction, life and death, endless renewal. And to add to it, alchemy itself has two dragons/serpents that circle each other, who are stated to be black and white.
With these themes of duality, that naturally works off Marinette and how she is. Between the two official leads, Marinette is the one that better reflects yin-yang and the concept of duality. Marinette works off her head and her heart. She can be the leader and the follower. She can take action but will also be the nurturer. She can be clear and open but also secretive and elusive. She can be chaotic and all the place, but also work off structure and have her own order to work off of.
And, ultimately, the biggest show of this is her being able to use both Ladybug and Cat with no issues with either.
And for healing, Marinette naturally is a provider, always stepping up to assist. And plays the vital role of healer in the field.
As for Marinette getting a pink kwami, what can be gained is her learning calm and tranquility.
And working off Koyll, I don't have her all down yet as a character, though she's more coy and fast acting to contrast cautious Wayzz (and the go with the flow Sass), so she'd click with Marinette being quick to respond, but push to be more open on possibilities, not everything has to go as Marinette wants them to, and she can't be as controlling as she would like. Also probably challenge Marinette being more tolerable, as to counter Sass more, Koyll is more willing to "bite" back if something rubs her wrong.
Now, on the reverse, I can think of some merits to work off of.
Turtle can naturally work off Marinette's nature to provide and assist, secure safety and stability. Marinette herself can also be a risky taker. Usually it's calculated risk where she likes her chances of coming out.
Canon's initial test was the riskiest test we've seen, and despite the lethal risk, she ran out to help Fu. And for this small moment, it's says a lot about her character. For at canon, she's at her lowest point, low self esteem, no confidence, and no hope for a good year. And despite that, she saw someone in trouble and rushed out to help them.
It was such an iconic moment that even the movie kept it in and expands upon it.
You even see a moment of her putting herself between him and the car, ready to take the hit before he does. This not only proves her as a hero, but confirms her as a protector. And you know, side note, I do prefer movie's take on this over the show, not just expanded detail, but the factor that movie wise, this incident is an accident vs show's Fu intentionally putting her in danger of getting hit by a car.
So, not only does Turtle work off her nature, but it also works off providing self-defense, to prioritize herself when she doesn't.
Wayzz would also be a good kwami to work off of her, having the appeal of being calm and reasonable, so when she starts to spiral and could get emotional/reckless, he can ground her.
Lastly, she does need to learn to withdraw more. She has a tendency to over involve herself, solve problems that aren't her own and shoulder too much (which can work off the World Turtle).
She does need to learn to ease back, that she's stretching herself out too much. And this being an animal known to withdraw into itself, could be helpful.
Now Felix with Serpent I can also see merits to.
Right off the bat, he does click with the more negative associations to serpents/snakes, being distant and aloof, vindictive, deceptive, and being a risk that will strike out.
But this can set up Felix growing to work off the more positives of serpents, from the creativity, to the guardianship, to the healing. Felix for sure is set up to learn to be a guardian, a hero who protects others, and to learn to be a healer and provider.
Felix getting a pink kwami can work off him needing to learn to be a more loving person.
And Felix with Koyll, I can't fully say yet, but she can definitely push for him to act instead of staying out of trouble, and to be open to possibilities and to roll with the chaos. Don't close himself to the world. Could even play into the theme of Ouroboros, needing to self-destroy to begin anew, especially as he starts antagonistic, and is set up to grow and redeem himself, and Ouroboros is a good theme for a redemption. It makes Serpent a pretty iconic animal for Felix to have on his path to improvement, how his nature and who he is will be challenged as he walks forward, and how he will change.
