I was just reading about Tonrak and Tribal chief and whatnot, and I thought of something weird: Since Tribal Chiefdom is passed down to the eldest son of the then-Chief in the Southern Water Tribe, who would Tonrak and Unalaq's father be?
So I did a little bit of research, and as I'm typing this, I'm still doing fact-checking. Everything works so far, and everything matches up perfectly. This is my theory:
SWT chiefdom is like Fire Lordity or Earth Kingism; it passes down to your eldest child, unless something happens that makes it so that it goes to the second-eldest.
Tonraq and Unalaq's parents have never been revealed. The most we've got is a mention of Unalaq's father in some mobile trivia game, which doesn't say his name.
Sokka died between 158 and 170 AG. How he died is unknown, but it's been shown that one doesn't have to die in order for their eldest to become the next big guy, as Zuko abdicated his throne to his daughter Izumi.
Unalaq's reign as Chief of the SWT started before 158 AG, the earliest date in which Sokka, the previous chief, could have died. It was never stated or implied that the STW royal family changed families, and there was no reason to.
Plus, they all have brown hair, tanned skin, and light blue eyes.
Now, this brings up another topic. Since Sokka was Aang's brother-in-law, does that mean Korra has Aang not only as her past life, but also as her grandfather-in-law? How would that be possible? Although, Korra wouldn't be Aang's direct descendant, just an in-law, and they're still from seperate nations.
Let me know if there are any holes or more evidence in this theory, and let me know what you think. All my sources are from Avatar Wiki, nothing is made up, so don't worry about any false sources. I don't care if you fact-check my theory evidence if you're a skeptic. Trust me, I did that a lot.
The Southern and Northern Water Tribes were both ruled by Unalaq. Unalaq and Tonraq were both from the NWT. Korra isn't closely related to Sokka or Katara, at least from her father's side because he's from the NWT. She could be related to Yue though because when Cheif Arnook died, the throne was probably given to someone he was related to.
Anything's possible, really. All we know for certain is that Tonraq was next-in-line to succeed whoever was the current Chief of the Northern Water Tribe until Unalaq arranged his banishment, after which he made his way to the Southern Water Tribe, and eventually became Chief of the South. We also know that the Chief of the NWT technically rules both the NWT and the SWT (at least until the latter becomes independent in 170-71 AG or thereabouts).
That said, I think the idea of a blood relationship between Tonraq and Sokka is rather unlikely, because Sokka is from the SWT by birth, while Tonraq is not. Could Sokka have ended up Chief in the North? Possible, but IMO highly unlikely. Much more likely, he remained in the South and was involved in the postwar reconstruction; we also know he served as the Water Tribe representative on the URN/Republic City Council.
More likely in my view is that Tonraq is distantly related to Chief Arnook; while we know Yue basically predeceased her father - with the whole becoming the new Moon Spirit thing, there's a lot we don't know about the NWT's royal family. To whit, Yue may have had a younger sibling who would have become next in line, whether already born at the time or born later; or perhaps Arnook himself had a sibling, and either that sibling or his eldest, as next-closest relative to Arnook, inherited the position following Arnook's death.
This all supposes that Sokka and Katara were not descended from NWT nobility which is VERY likely. We KNOW that Sokka and Kataras paternal grandmother was from the NWT and more importantly was betrothed to Pakku, a highly placed member within that tribe. Betrothals are 1- usually reserved for noble families to consolidate power and wealth and 2-generally between TWO such families. It is highly likely that Kanna was from an influential family, one influential enough to arrange a marriage to a man who would later be on the NWT chiefs' personal council, and that she bailed, fled south, and that her son became chief of THAT tribe.
I have this weird theory that Bumi might be Tonraq's Father and Korra's Grandfather. Since Bumi and Tonraq display leadership, physical strength, and charisma. Plus they both have similar facial features. But that just my opinion.
Bumi is at the very, very most perhaps 18 years older than Tonraq.
On the Sokka theory, reasons against;
Korra never addresses Katara as Aunt or Great Aunt.
Sokka would have been a little more understanding and perhaps made Tonraq fix his mistakes.
Sokka would look exceptionally old for 66 in that flashback in 151 AG.
Finally, how on earth would he have a son like Unalaq?
In modern day the southern water tribe cheifdom is no longer a monarchy but elected, implying that the new, independent Southern Water Tribe is a more democratic society, also I believe that Sokka was just a minor chieftan.