So if Zuko and Katara are both dead, then who's ruling the Fire Nation?
Azula, maybe?
Or maybe Sho and Mai took the country by force with this mysterious Agni Army?
That looks likely now. Maybe it's not Fridge Logic just yet.
If Lilith and Kuzon are bully meat for their parentage, why isn't Miracle? Sokka/Azula is just as much a mixed marriage as Zuko/Katara, and it's probably no secret that this Azula and the former Fire Nation Princess are one and the same except for the hair and personality transplant.
Three words: Azula is terrifying. Scaring those brats away from her niece and nephew is the first uninterrupted badass moment she has in this series; the kids have probably learned from bitter experience that teasing Miracle is a BIG no-no. They suffer from Aesop Amnesia in that they think Kuzon and Lilith are free game, though...