OK, so...
Given the only mention of Azem's name (title) comes from Emet-Selch's dedication embedded in their memory crystal, and the only person who heard it was us, for anyone else to know Azem's name / title we'd have to be the one to tell them until it becomes common knowledge (though I doubt that'll ever happen). So... inference, but yes, we are the one who told the Scions.
As for Emet-Selch mentioning that Ryne is an "underwhelming reincarnation [of Minfilia]," that's implied to be because he hadn't worked out that Ryne was not a reincarnation of Minfilia despite possessing (some of) the Oracle's power(s). At the very least, no conclusive evidence that Ryne is a shard counterpart to Minfilia has been given; she doesn't appear to have the Echo, didn't awaken it during the starshowers of 5.3, is only immune to tempering thanks to Minfilia's presence and/or Hydaelyn's blessing (re: placebo tempering), and hasn't ever heard Hydaelyn's voice. Oracle or no...