Most anime series only have one resident bifauxnen, whether her name be Haruka Tenoh, Falsetto, Akira Kenjo, Seira Azuma, Anna Hart, Benio Amakusa, or whatever.
The Westeros universe, just like Sakura Wars, overcomes this limit by showing us the different flavours that bifauxnen come in...
EXAMPLES IN ANIME: Falsetto (from Eternal Sonata), Seira Azuma, Akira Kenjo/Cure Chocolat, Haruka Tenoh/Sailor Uranus (after joining the Inners and not to the Inners; the trope codifier), Anna Hart (after solving her dad issues), Rei Hasekura, Amane Ohtori, Lucrezia Noin, Ryuken Ishima...
This is the Princely Young Man-flavour kindly bifauxnen, that acts like a knight, prince charming, or the women's ideal man (handsome, thoughtful, romantic, cultured...) Used to wear long tresses (think Utena, Oscar de Jarjayes...), but the advent of Sailor Uranus made this kind of character have Boyish Short Hair since the early 90s instead. Still, the essence of the character remains the same.
Brienne, the Maid of Tarth, plays this character straight while also highlighting a naiveté and insecurities that we very rarely see in any kind of bifauxnen. And we see her rose-tinted glasses fall off little by little as she comes to grips with reality, with her own strengths and weaknesses... for Westeros is no adventure-friendly magical land, but a world full of darkness and crud, isn't it?
EXAMPLES IN ANIME: Haruka Tenoh/Sailor Uranus (to the Inners before joining them; the trope codifier), Leni Milchstrasse, Maria Tachibana, Benio Amakusa, Anna Hart (before solving her dad issues), Kaname Kenjo, Akito Sohma.
This is the Sailor Uranus expy who gets allotted the role of the Aloof Ally, and thus, frequently given an "ice king" and/or "grumpy" personality to match... they form most often a Battle Couple with a proper lady Oneesama (another page out of Uranus's book). But Yara never does. Once more, our expectations are subverted. In some cases (see Kaname Kenjo, Akito Sohma), she may be a villainess of the sexpot baroness kind.
Yara fits, however, the general aloof bifauxnen template, only that our pirate queen is contrasted (instead of with an oneesama) with her effeminate brother Theon, seen as a failure to the Greyjoy surname. And there are no cracks in her armour. The result is one of the most badass sheroes in Westeros indeed. She does lose her throne and leave for the mainland on exile, but her journey is not fruitless at all... but the most striking difference is that between the hot-blooded Yara and all those cool-as-a-cucumber aloof Uranus expies!
The Tank/Thug Bifauxnen: Maege MormontEXAMPLES IN ANIME: Kanna Kirishima... I cannot think of any other example than Kanna Kirishima. Maya Yookoo may fit as well...
This is the rare female example of a Large Ham Bruiser. Frequently a hard drinker and/or a brawler, this badass has a bodybuilder physique and pec-like bosoms to accentuate it, as well as being as tall as she is muscular. In spite of being such an imposing sight, she has a heart of gold. She's frequently also older than the usual (late-teen or early-twentyish) bifauxnen, being in her thirties or forties (Kanna is late-twentyish, so it counts, idem Maya).
Maege does not only fit this characterisation; she is also a family woman and quite the mama bear (pun intended) with whose five daughters you would never like to mess!
This one is a child or pre-teen example: they may be either a princely young boy/lordling or a plucky ankle biter, or change from the former kind to the latter if faced with a Copernican twist of fate (this is the case of Arya herself).
EXAMPLES IN ANIME: Yuri Miyazono, at 15 and in secondary school, can be seen as a borderline case of kid bifauxnen, attending secondary school like the leading characters and, despite wearing a skirt (like Akira Kenjo) as part of her school uniform, playing the male lead role in the School Play. Another borderline case would be Shizu Shido. Riccardo Russo of Baccano! fame is also a younger, pre-teen kid bifauxnen about Arya's age. Character of the Week Yuki Tachibana (Alex in the Anglophone dub) from the Silence card episode of Cardcaptor Sakura Season 1 is also a kid bifauxnen.
However, unlike the shy Yuki, Arya has more of a backbone. In the fact that this is her coming of age, her character arc is far closer to Riccardo's. But Arya reminds me the most of Yuki, what with the dark hair and being daddy's girl and, after losing her father, having to become strong for his sake, no matter if she has to mistrust others for fear that said "friends" turn against her... Only that Arya, being instead a POV lead instead of a Victim of the Week, is far more fleshed out.