Will Amumu still becoma a human-child mummy instead of a yordle-mummy?

They should give Azir and Amumu special interactions. Like when Azir sees Amumu he says things like "Noooooo! This can't be!" and "Not again... now all is truly undone!" but we have no idea what he's talking about (and neither does Amumu presumably).

The merchant of Aram says that he is a yordle, and he always will be

His character page is affiliated with Bandle City, so probably not.

Amumu is Azir's son. Amumu died at a young age. While exploring Shurima, he stumbled upon the entrance of a cave that was very interesting - different from anything Amumu had ever seen. There were crystals, glowing purple, in every crevice of the cave. Interested, Amumu went in to explore the cave. What Amumu witnessed in that cave is unknown. Amumu's corpse was found at the entrance of the cave with a large gash in his chest. The party who found Amumu searched the cave he laid outside of, but they found nothing but an small dark room, completely empty. They returned his body to his family. As tradition, Amumu was wrapped and sealed away in a tomb for all eternity.

Or so they thought.

I feel like something similar to this is going to happen.

I hope he becomes a child, so that I can ship him and Annie perfectly! ^.^

I really look forward to whatever Riot has planned for amumu. He was the only one who didn't receive a texture update or VU before or during the Ascension event....

He was also missing from all the cinematics etc but i guess this was to maintain his mysterious background.

Hope he gets some love soon.

Overall it was never said that they will retcon him for sure. People only started to assume this when his short lore didn't mention if he was a yordle or not.

As for now we simply don't know what he is,he might be a yordle,he might be human,he might not even know it himself.