The State of the Ascians (Assume Spoilers as of TODAY)

[Cilia]

... Emet's soul seems to be chilling in the Lifestream because he can answer Azem's crystal call. Does that mean that the Unsundered, while out of the scene, have been untempered through their corporeal death? That could be certainly interesting. Opinions on this?

If the logic we're given in 2.0 still holds true then yes, return to the Lifestream does undo tempering. (Ascians' corporeal forms can be repeatedly killed to no end due to their ability to cheat death.)

I agree, even if this places the player character's backstory in a bad light. Which leads me to believe there is a third, better option than summoning Hydaelyn or Zodiark. What that is, at this juncture, doesn't appear obvious to me.

Furthermore, if we are Azem pursuing the third option, how did we end up being Hydaelyn's chosen? Wouldn't picking us be a mistake if we ever figured out who we really were and learned about what happened in the past?

If we're to take Emet-Selch's account at face value, summoning Zodiark was a grim necessity to stop the Final Days. Summoning Hydaelyn was never a necessity, but a world where life exists as nothing more than livestock to feed a false deity in exchange for "miracles" has so many problems it's unreal. Third options are nice to have or try to make, but due to time constraints or unwillingness to compromise, sometimes there aren't any to be had.

We don't really know what Azem did in response to the summons. Something to keep in mind however is that we are not Azem: we are our own person, even if we have similar tendencies and possess (most of) Azem's soul. Further Azem's defining characteristic was aligning with anyone and everyone to do good; while s/he may not have condoned the summons of Zodiark and Hydaelyn, if their goals aligned there would be no reason not to work with them.

Us being "Hydaelyn's chosen" has less to do with Hydaelyn choosing us, and more to do with our innate goodness catching her attention. Lending us her power could backfire if we learned the truth, but given our goals in-universe have only ever been to protect Eorzea from those who would do it harm, it's a pretty low risk to take. Hydaelyn does not and never has demanded blind faith and obedience in exchange for her favor. In fact it appears that Hydaelyn places blind faith in mortals she thinks will advance her cause, even if that ends up not being the case further down the line (such as Saint Ajora and the Warriors of Darkness during 3.X).

We don't expunge primals, halt Gaius' ambitions, end the Dragonsong War, liberate Doma and Ala Mhigo, or rail against Emet-Selch's plans because Hydaelyn tells us to. We do these things because we have to, because we are compelled - not by Hydaelyn, but by our own conscience.

... that's how I see it, anyway.