What I understood from the end of CS was that Ragna undid the change from Noel to Mu. So now it turns out he just undid the brainwashing that Hazama did to Noel. She should still retain Mu's abilities, wouldn't she?
Stupid or not, they managed to make the inclusion of Mu canon. That's something, at least.
Edit: Seems like they reworked her Astral too, about damn time lol. The current Astral looks like ass (pun not intended)