The designs of the characters in Disney Mirrorverse are extremely modified and look very fanmade. It’d be pointless to give them costumes 
Oh right, I missed the mirrorverse stuff. No idea what that is to be honest 
A shame they aren’t making more outfits for the game, I really like the idea of alternative versions of our favorite characters. Well even so, I still have my own ideas on costumes that would have been great to see:
Mickey, Donald, and Goofy - Kingdom Hearts outfits
Baloo and King Louie - TaleSpin outfits
The Disney Princesses - the comfy clothes from Ralph Breaks the Internet
Inside Out emotions - versions from other characters like Riley’s parents
Robin Hood and Little John - their disguises
DuckTales characters - reboot designs
I love that idea! But don’t revive dead topics…