Hey remember that post on how the Kokiri in Ocarina of Time had gendered clothings and Link wore a set of a mix of the boy and girl clothes ? Guess what ? They did it in Twilight princess too ! (honestly this may have already been pointed out because the games is more than 15 years old but I'm making my own post too for reason)
Look at the girl's outfit in Ordon Village :
And here are the boy's outfit in Ordon Village :
Alright so the main difference is that Women wear pants while Men wear a sort of long skirt (I'm sorry if it has a name that I don't know).
Smaller differences are that Women tend to prefer short shirt that they put underneath their garb with little to none decoration on their clothes. While Men tend to prefer long shirt/tunics with their 'skirt' underneath (unless those are long tunics with the end being in a different color ? idk maybe both are present) and a sort of apron(?) over it and have a lot of decoration on their garbs which feature a very specific belt.
You can note Women do have those apron(?) too, just like Men can have shorter shirt too. It's just rarer, less popular it's seems. Also young boys don't have long tunic like their parent so I guess it's considered like are considered for adult ?
Anyway by that logic those outfits :
seems to be gender neutral :). Maybe you could think that it's just more practical for their job except Link has the same one as Fado who is wearing traditional boy clothing and I would like to show that at Ordon it's perfectly acceptable to put a relatively short tunic with only underpants underneath as proved by Mayor Bo :
And although it does seems that Illia and Link dresses in a way that calls back to their parents (I'm talking about both Rusl, Uli but also Fado in Link case) which very heartwarming but they could also have gone into a more gender-conforming way to do this.
So in short : enby Link, Illia and Rusl solidarity (no wonder they are close).
Oh and @childrenofordon this might be an useful reference :) (you're doing god's work, thank you)