As far as we can tell, the Nu-Mantia Intercept was basically an older version of the OB main quest that got scrapped in favor of a Daedric invasion. Knights of the Nine is obviously inspired by it, and you can argue that Mankar Camoran was a harbinger of their return, trying to create a new Ayleid Empire in the New Dawn, but the specific Ayleid threat mentioned in Nu-Mantia is, for all intents and purposes, non-canon (as uncomfortable as I am using that word).