Story Elements that need to be added or improved:

[Fendred]

I agree with this.

After all, there is one pretty important Echo involving a certain Ascian explaining this pretty well...

Care to point it out? Telling me it is "important" doesn't tell me jack about what you are referring to. The thread is already spoiler territory. If you are referring to the new 2.1 cutscene where it is clear only minfilia can see Elidibus, that doesn't really suggest much of anything other than they can go invisible. They still present themselves in their robes and make no effort to hide that they are Ascian. Also, if I can't recall any cutscene justifying the Ascians as actually deceptive, that is not a good sign in terms of square's storytelling, which would bring me back to the point I made. It really doesn't have anything to do with any special power the adventurer has. If they don't show ascians being effective deceivers, I have no reason to believe they are. It's that part of storytelling called show, not tell.