While they never directly came out and said it, I came away from the Moggle Mog quests with the impression that the Mogsguard WERE tempered, and the other Moogles planned to remove them. Probably not kill them; Moogles seem too mild-mannered for that, in general, but quarantine them, at the very least. (And not too effectively, given that they were able to summon Mog EX.) Just my take on things.
No need to be vague about gender. We know from both the Sahagin Beast Tribe quests, and some Ondo side quests, that surface dwellers rarely or never see Sahagin females. Every Sahagin we meet, including the Priest, is male.The Sahagin Priest who summoned Leviathan was definitely not Tempered, but acted just as fanatically as their followers.
It's been my impression that the Black Knights are considerably more vocal than the White. And, honestly, they have to be, in order for their suspicions to not be dismissed out of hand. This game practically beats the player over the head in its efforts to depict Hydaelyn as a benevolent, earnest character. All of the "suspicious" behaviors she exhibits? The characters in-game have the same information that we do, and none of them have shown any signs of losing faith in Hydaelyn's goodness. Even Yoshi P is giving the players the side-eye for throwing Hy under the bus at the word of an Ascian, of all people.
The writers seriously do not seem to be trying to paint Hydaelyn as a morally grey character (let alone black). Characters in-game that are considered to be extraordinarily wise, such as Loisouix, believe in her benevolence, and for SE to turn around and pull a "twist" that reveals she's actually full of dark intentions would essentially be painting these characters as fools. I just don't see that as being in the cards.