Miraculous AU/Canon Divergent resource material:
Hi there! I was thinking about some canon divergent situations where the villain held a different miraculous and nooroo was in the hands of Marinette. However, I was struggling to define some elements without opening a wiki page every 5 minutes so here's a breakdown of how Miraculous design currently works in canon and consideration for how the currently shown miraculi could be used in a standalone setting (As of Season 3).
Each miraculous tends to have a similar transformation sequence. For instance; Mr.bug and Lady Noir do the same general motions as Ladybug and Chat noir.
Almost every hero sequence has the character do a swiping motion for their mask, it is always at the beginning or end of the transformation.
The 3 acceptions to this are Carapace, Pegasus, and King Monkey. Carapace and Pegasus's divergence is due to their owner's glasses. King Monkey is less certain but it seems to be due to a more complex headgear.
Adults transforming is a lot less complex, they are changed in an unmoving standing position.
While outfits are tailored to the wearer, each miraculous always has the same weapon which stays the same in appearance.
The peacock miraculous does not have a mask. This is not due to Mayura being corrupted as we see the same look in Fu's backstory.
The power ups are wholely worth ignoring. They've functioned between extraneous to world breaking. The power ups (and unifications) seem to exist to diversify merch and would otherwise not have been included in the story. My reasoning to this is the fact they appear suddenly with no build up, most aren't shown off beyond their debut episode, aren't used where they could be, and were all given to LB/CN at once rather than a slow accumulation over time. LB needing a water power up while also being able to use her yoyo as a rebreather is evidence to this obtuseness.
How each Miraculous could be used:
LB/CN don't need to be examined; Ladybug is fundamentally incapable of being used as a villain and Chat Noir's power acts the same no matter the alignment.
The butterfly Miraculous can make Akumas or create additional aids in fights functioning similar to lending Miraculous to other characters.
The peacock miraculous effects people emotions. It functions pretty much the same to the butterfly Miraculous with Amoks. When not paired with Hawkmoth, the peacock can still create a villain of the week situation. It could manifest weapons for a general criminals/people they manipulated into wanting to harm others. They could also simply summon a new monster at will. For a hero role it would work the same but more likely the user would rely on the target's current emotion and only use emotion manipulation in a theraputic way (ex. Calming the target and addressing the feeling without forcing them to feel that way.)
The fox miraculous is pretty straightforward as we've seen in canon how it can be used for good and evil. Likely unable to act on its own since it isn't offensive in nature though it could be used for Mind Games and Misinformation in a ooc story.
The turtle miraculous is more of a support role. When used creativity, it can disarm a person or trap people. For a villain, this could be holding people hostage or ensnaring enemies in a challenge (such as a flooding space.
The Bee miraculous can function as a foil to Ladybug since they have similar motifs. In a situation on their own, the bee miraculous immobilizes/disarms their opponent. However, this would be hard to use in a villain role as fully numbing the target would be a game over. Would work better if changed to only able to only immobilizing a body part or afflicting over time.
The Dragon miraculous has weather powers. The wearer can easily be used as a standard superhero/villain with melee combat. Would also be hard to catch the owner as they can turn to wind.
The rabbit miraculous is overpowered. If the user is given restrictions either on their own principle or the laws of the universe, their potential would be more reasonable for a regular appearance. In a villain role, it would be more apt for the user to summon a champion from history or have a limitation to how much time hoping they can do. Since Ladybug is a historical figure in the MLU, there could be interesting mashups.
Similarly, the snake miraculous is too powerful. Having a redo button would be hard to defeat unless the redo was finite. Opponents fighting the snake user would need to strategically plan around the ability. As a solo hero, they would need to solve a way out of their situation (think Madoka where redoing doesn't guarantee a good outcome). As a villain, heroes would have to create a plan around someone essentially being able to see ahead into their future.
The horse would be a reasonable opponent against LB/CN. So long as the use doesn't instantly kill them, ladybug's charm would presumably restore everything to where it was including the heroes. It could be used offensively to throw something at their opponent or move their opponent into danger/confinement (which works both ways).
The monkey miraculous has the power to "disrupt" how something normally functions. For a villain role, it would likely be a "oh no the train is out of control" scenario. When fighting alone, the situation is won whenever they stop the other person's weapon.
The mouse miraculous has versatile use. Through multiplication, the user can do reconnaissance, stealthily get into locations, multi task, and swarm a foe. This can be overpowered if not matched against a proper opponent.