Avian: Officewear for work, the official Macro Cosmos uniform for work events. A dragon gym uniform (unused) and... not a lot of casual clothes. Avian doesn't treat himself well so he has like 3 casual outfits he rotates between.

Stahl is a corporate dad. Along with formalwear and well tailored suits, when on the down low out of the public eye, he probably has typical dad outfits: polo shirt tucked into shorts with a belt, white trainers, socks pulled up high etc. He also has a number of alolan shirts.

As for Arryn, she has a large wardrobe and something of a fashionista. She's proud of her physique and is happy to wear short dresses, skirts that shape her body or show off her arms and back. However I am not fashion oriented so these outfits are hypothetical at the moment.