Judging from this scene, which is again very hilarious, would it be ok to say: ‘They are wearing the exact same clothing.’?
Would it also be ok to say: 'I’d really hate to show up in the same outfit as you or should that be yours?
“They are wearing the exact same dress.”
“Dress”, or in this case “costume”, carrys the idea of style or maybe a desire for uniqueness.
Clothing is boring. I wear clothing.
“I’d really hate to show up in the same outfit as you [show up in].”
“… as yours” sort of works, but I don’t think it’s as clear.