Ok first of all Tonraq and Unalaq are not Sokka's children. There are theories of their father being Hahn, Yue's betrothed. We don't know if Sokka married Suki and if either of them had children.
What we do know is that yes, Tonraq married Senna. Unalaq married Malina(there r two Malina's Unalaq's wife and Hakoda's second wife. Tonraq had Korra and Unalaq had Desna and Eska.
Sokka was the Southern Water Tribe councilman on the United Republic Council. BUT, he was also (not sure if it was before or after) the Head Chieftain of the Southern Water Tribe. The Head Chieftain is sort of like a governor-general or viceroy. I'm pretty sure the Northern Chief elected them. The Head Chieftain governed the South with the help of the smaller tribes' chieftains and tribal elders. Sokka was Head Chieftain like his father Hakoda was. Hakoda was the first Head Chieftain after the war.
