"I really think more [ATLA] fics with polygamy would be interest[ing]."
https://www.tumblr.com/zuko-always-lies/766526980525080576/i-really-think-more-fics-with-polygamy-would-be
What do you think about ships like Mai/Azula/Zuko, Ty Maiko, Ty Lee/Azula/Zuko, Maizulee, and Mai/Azula/Zuko/Ty Lee in the context of Fire Nation Royalty engaging in polyamory?
Also, if you have read fics dealing with each of the previously described ships, what are your thoughts on them? Are they anywhere near historically accurate, or they just smut fics?
Furthermore, how would you write the ships to be historically accurate?
Warning: I will be talking about incest here a bit.
Let's start with Azula/Mai/Ty Lee. There are a good number of good fics for that ship (for instance), but generally the social, cultural, and political implications are not a focus. The best way to make the ship a little more grounded is to present it as something that is going on in addition to fulfilling their cultural responsibilities for their families, not as a replacement for "conventional family life." As long as Azula and Mai (Ty Lee burned her bridges with her family long ago) are marrying the right men (thus making family alliances) and producing heirs, no one cares about them being involved with each other.
Another realistic way to approach this is to have Mai, Azula, and Ty Lee all be wives/secondary wives/concubines of the same man. I suppose that's where the other part of your ask comes in.
So, I'm actually beta-ing for a Azula/Mai/Ty Lee/Zuko fic right now. However, in general you are correct, most fics of this type are just smut. That's fine, of course, but not what you are looking for.
Let's deal with the incest aspect of this first. As far as I'm aware, this is not something any historical East Asian or Southeast Asian royal dynasty engaged in, but there have been many royal dynasties who have.
Any sort of Azula/Zuko relationship, at least an official one, only makes sense if the Fire Nation royal family has a tradition incest. Otherwise it's not going to be culturally normal enough for a marriage to happen. However, if there is such a tradition, then suddenly the marriage makes a tremendous degree of sense as a way to submerge and eliminate Azula's claim to the throne. As I'll discuss below, there is ultimately only one primary wife on top of the household hierarchy, and if this status is denied to Azula in favor of someone else, it would be as a deliberate slight or humiliation against Azula.
OK, now there are three or four purposes to the artifice of polygamy in East Asia:
As a babymaking machine, to ensure plentiful heirs (and the status of women inside the "harem" tends to be influenced over whether they've given birth to children).
As a status symbol; having many women marks you as wealthy and powerful.
As a source of pleasure and love.
As a way to establish connections and alliances.
The same trends can be seen up and down the social scale, with households of more modest means being smaller, but of course households needed to be of some means to support more than one woman, much less many.
Harems were also structured as a hierarchy, with the primary wife on top (although she would be below her mother-in-law), and then secondary wives/concubines and so below that. Imperial harems in particular had a ton of ranks and titles to them.
By the late Imperial period (Song/Ming/Qing, but not Yuan) the women of elite households were very cloistered and confined (although arguably in the Ming Dynasty that's also true of even the Emperor), but things were less like that in earlier dynasties and other East Asian societies, to a variable degree, and in the Shang Dynasty (which was more or less the dawn of Chinese history) palace women even seem to have regularly led armies in the field. I think that's a bit closer to how the Fire Nation would understand the institution, to say the least.
There are also some other things I should bring up:
For the Emperor, monogamy really wasn't possible, even if he wanted it. There's entire systems pushing him toward polygamy.
There's a huge reputation for vicious infighting between women over status in Chinese harems.
For many women, concubinage was a ticket toward upward social mobility.
Harems can be large, particularly for the emperor. Japan and Korea generally seems to have had smaller households, though.
A common trend (far from universal) is to have children born of concubines adopted by the primary wife.
A lot about this system might sound very depressing (and it was) but I just want to present one counterexample from the famous memoir Six Records of a Floating Life by Shen Fu. Shen Fu was an intellectual of extremely modest (or worst means), and, beyond the struggle to keep going the book is largely about his very happy marriage with his wife Chen Yun and his grief over her untimely death. At a certain point, despite the couple having very little money, Chen Yu gets obsessed with finding a beautiful and charming concubine for her husband, an idea Shen Fu is cautious at best about. She eventually finds a younger girl, Hanyüan, that meets her standards, and basically seems to fall in love with her and become obsessed with her, a feeling that Hanyüan reciprocates (this is a 19th century Chinese text that I'm reading in translation, but what's going on between them seems very homoerotic). Chen Yun tries very hard to add Hanyüan to their household, but eventually Hanyüan was forcibly married to someone else, and Shen Fu blamed the grief over losing Hanyüan for Chen Yun's death.
Anyways, enough prattling. I know what you really want to know is my opinions on Zuko and polygamy. These are the points I think are worth hitting:
For FN society, Zuko's polygamy would primarily be seen as a babymaking machine (and perhaps as a reaction to the disadvantages shown by the monogamy of Ozai and Azulon).
The lack of heirs in the royal family might play into things.
Zuko's consorts would not have the same rank. Only one can be his primary wife.
The high-ranking consorts would have very high social status in the Fire Nation. And in turn (to a much lesser degree) Zuko might gain status by having high-ranking women in his harem.
There would be no reason that people would expect that Zuko would stop at two or three consorts. Especially if Zuko's "harem" was small, people would shopping their eligible daughters to him, and so on.
Attractions between women within the harem would be none of anyone else's business.
I would expect though that Zuko would be reestablishing royal polygamy, if he did it.