I FINALLY FINISHED MY KATRIELLE MOVESET IDEAS!! Check it out here!!
https://docs.google.com/document/d/1ASfwRikI4RCDlLdEuZbEdt8t6Lgd5sDJDSDNVffNvj8/edit?usp=sharing
I am atrocious at making movesets so I am open to suggestions! I also edited the doc with some more information based on later DLC and the Switch release.
I like it! I like it a lot! Here are some thoughts:
For costuming, I feel like swapping one of the generic outfits out for a Flora cosplay would make sense. She's a popular character and also looks a lot like Katrielle, so she'd fit. I believe her outfit was also exclusive to the 3DS version, so there's that.
The idea of a magnifying glass move that incorporates the Layton cursor as a projectile is one I've heard a few times and absolutely love. It works especially well for Kat given her signature weapon... I also like the idea of her having a clue-throwing move that works similar to Teddie's item throwing in Persona 4 Arena - items with different properties appear in a set order to make a trick character without the RNG of Hero.
If she were to come out alongside her father, I really like the idea of having a case solved final Smash - it's a way to make her uniquely Katrielle while also having a kick-ass CG final Smash. If she's by herself, then I think one where she summons her friends is more appropiate for fan service purposes.
I feel like she could have just the L in a circle, without her or her father's hats, if they wanted a generic series logo. She would need to have a stock icon that adapts for her headgear/glasses.
The idea of a real-world location being in Smash Bros is something I've kind of wanted for a while, but they seem to have resisted it every chance they have had... It'd be cool if she did get a traveling London stage, but I do wonder if she'd just get something based off of an earlier Layton game set in a fictional town.
I like all of your CSS reference images. Her holding her magnifying glass is my favourite; I think.
For music, I imagine Kat's main theme and the LMJ theme are both compulsory obviously. I feel like you could medley together some puzzle-solving themes. Then start collecting other main themes? Again, this would depend on if it is just Kat or Kat and the prof together...
As for taunts, whether or not her father is a separate character, I feel like at least one of her taunts would have to have her self-identifying as a gentlewoman, as that is kind of a trope of the whole series. Having at least one of her taunts be her being silly would be very in-character too though.
Overall, I really like this moveset and concept! Great job on it and good on you for supporting an often overlooked character.