So, is that a dagger? (In the new concept art.)

[MStowastiqVahlshdeh]

There is a low level male mage skirt/pants armor called Acolyte's Skirt and it is brown but the flared out shape is at least similar to the one that the miqote is wearing in the artwork, the one people are referring to as a skirt being a declaration of that miqote as female gender. So the skirt is not necessarily confirmation of female gender.

Also, in the game, it actually has pleats similar to a girl's school uniform skirt and flares out much more than the one pictured in the Acolyte Skirt armor info at the lodestone. Worn with knee high boots, it looks even more like a skirt because it hides the pant legs attached to the bottom part.