I've always liked the Viera, especially the ones from FFXII, and while there are decent Fran Lora, there haven't been any of her adorable sisters, especially Mjrn! I have attempted many times to make a decent Lora for her in PDXL and now Illustrious, and some are better at certain things than others. Overall, it's probably the best version I've done though a bit inflexible.

Recommended strength 0.7 - 1.0 / Seems to be hit or miss with other Lora.

Overly Detailed Tag Guide

Mjrn - Activation

rabbit girl, Viera - Help to strengthen her appearance, though sometimes "Rabbit Girl" can bleed onto other characters, including men. Specifying "Human male, generic male" and adding "Rabbit ears on male" to negatives can help with that at least.

topwear, legwear, underwear - Her outfit. Will appear without prompting, but can be used to kinda divide her outfit in half by adding the other to negatives. "Underwear" isn't needed, but sometimes her outfit gets a little off model around the pelvic area without it. Her outfit is unfortunately extremely strong, so will resist attempts at dress up and will usually just cut her outfit into the shape of what you prompt. Adding these to negatives can kinda help, but the best bet is to reduce the strength overall until it starts letting you change her clothes as desired. Some clothes seem more finicky than others, so it will be mostly trial and error. Fortunately, her main look is pretty consistent, and you usually should be able to get most clothes without going lower than 0.7 strength.

high heels, stiletto heels, hair ornament - Will appear without prompting. "Bare feet" will of course get rid of her shoes, but "hair ornament" can be added to negatives if you want it off, though it tends to be hit or miss and you will probably have to start reducing strength.

long nails, claws - Will usually appear without prompting, often on other characters as well, but this helps strengthen it and make her look closer to how the FFXII Viera look. Also effects her feet claws. Sometimes her hands can get a bit muddy, so this can clear them up a bit. Adding this to negatives can sometimes help prevent it from bleeding to other characters, but not by much unfortunately.

makeup, lipstick, eyeshadow, eyeliner - Most models by default will add a bunch of makeup to characters, but the Viera don't really look like that in canon. Adding these to negatives helps make her look more natural and close to her in-game look, but it's entirely a preference thing.

Enjoy this very niche / obscure bunny waifu!