I also fit mostly in the #4 category, but sometimes 3, or 1 & 2 a few times. But mostly it's a fetish rather than just wanting to look pretty. I can enjoy the little girl sissy look as much as wearing high heels & a sexy tight corset or girdle.
I would imagine if male & female clothing was identical, that people would still have the desire to wear costumes, play "dressup" & role playing games for fun, fantasy, or erotic play at least for a few hours once in a while.
Sometimes silky, smooth, or skin tight, or frilly clothes have an interesting or erotic feel & attraction no matter what sex they were intended for. Let's not forget, that even women can feel sexy when wearing their sexy female clothes. She is not trans but may actually enjoy sexy, fancy, but sheer lingerie or heels & a corset.
Heels & a corset aren't really comfort-wear, so there must be a reason some (but not all) women like to wear them, even when not talked into it by a boyfriend.
There will always be some people who will want to dress up as, or act out the role of being a princess, knight in shining armor, Superman, slave girl, ballerina, fireman, or GI Joe.
Even if male & female ballet costumes were the same, there would still be people who want to be a ballerina, or at least play one for a little while.
In it's most basic form, you can look at a house cat. Without any prey in the house it will stalk & attack a pet toy, it's owner, or another cat in the house as prey even though the cat does not intend on hurting the owner, other cat, or destroy the toy. All in fun, the hunt must go on, even if there is no real prey around. Kitty is role-playing a fantasy.
Erotic attachments, & fetishes even go on in the animal kingdom too. Most indoor pets, not fixed, may try to mate with a stuffed toy, rolled up sock, pillow, another species of pet in the house (house cats, dogs, & rabbits under the same roof may try to hump each other), or your leg.
Your parakeet may get very aroused at your finger, face, nose, or just being spoken to & petted, or with a toy.
Many male birds will pay extra attention to their feathers & really show off their plumage elaborately to attract a mate... even spending a lot of time decorating their nest too.
In primitive tribal societies in hot climates where the natives are scantly dressed or almost nude, they will dress themselves up, decorate themselves, or paint themselves to attract mates or a permanent partner.