I think the Iron first side of the deal is showing sign of going away actually, if we take her conduct in the colonies as the style of rulings she want to implement.I doubt that would happen.
Akane herself stated her goals and focused her will around that goal a few updates back, where she was meditating with Azula.
She said that she will rule the world with an iron fist, and anyone opposing her would be cut down but those supporting her would have a good life. Anonkun's player base built it around that and the bases for it since the beginning. Which resulted in the current villainous imperialistic and perfect Crown Princess Akane.
The element of Fire is that of Will and to be honest, I don't see any relevant or sufficient enough reason for Akane to drop her ultimate goal nor for the Anonkun player base to do so after working to reach it for like 60k words long?
I doubt Azula would have any kid, Akane seems like she would be lenient enough to allow her sister to not marry if she wished to and Azula in the canon universe just kind of went power-hungry crazy, really. I just can't really see her marrying anyone. I mean, can you imagine her caring for a kid? Or just not fighting or training for 9 months? Impossible.
So, unless Akane goes for the sperm donation, she'll have to rely on Zuko to perpetuate the line as he did in the canon universe.
Her taking over the world would probably be the best thing for the avatar's world if she'll come to see that they are all the same people and that the divide of the nation is an illusion, just as how she is already starting to see that the element division is an illusion.
If she were to unite all the world in a paceful multi-cultural super-nation she would probably do Aang job for him. (And having Aang face the question of if the Avatar is needed anymore as an istitution instead of Korra could be an interesting narrative plot)