Did Elthina do the right thing by staying neutral?

I said already. As hawke could know if from Karras as source, Anders can know it from another source. It was a known thing. The fact, that Karras speaks about it openly, proved, no matter, Hawke killed him or not, or Anders was in the party when Karras spoke about it, or not.

If Elthina "sincerely" thinks, there's nothing wrong, Elthina is the stupidest thing in the whole Kirkwall. But she knows it. She speaks about with Hawke.

Nothing equal about this "two wrong".
Meredith has no excuse. Not the blighted red lyrium made her mad criminal, she was mad criminal in the Act1 as well. With Elthina's agreement.

The whole explosion proved, the system doesn't work. Also: Elthina never made Meredith less murderous. She just helped his crimes to keep behind the closed doors.

If he's not in the party then someone who was tells him about it.

If Elthina is so stupid as to believe that everything is fine even as her own direct subordinates have spent the better part of a decade flouting Chantry law, then that is all the more reason that she is unfit for her position. Leliana's lack of concern over Meredith's law-breaking is just another example of how Elthina is utterly failing in her duty to control her subordinates.

And Meredith had already decided that the Circle needed to be wiped out even before Anders involved himself. His plan never would have worked if Meredith had just executed him instead of Annulling an unrelated Circle. Your "two wrongs don't make a right" logic clearly doesn't apply to Meredith. And Elthina clearly wasn't keeping Meredith's impulses in check as proven by the fact that Meredith went over Elthina's head in the first place.

What Anders proved is that Templars cannot be trusted with life and death power over others. He proved that they cannot be trusted to obey their own laws. That's why at least half the Circles revolted on the spot when they heard what Meredith had done. The only alternative at that point was to allow a repeat of the Annulment of the Antiva City Circle.

This is what you think of people who disagree with you? Wow.

I guess I keep forgetting how inflexible you are.   Hope you are never in a situation where you have to make a choice like that. Something may not be "okay" but that doesn't mean it isn't sometimes necessary.

Most people have morals. How much are you willing to sacrifice to abide by them 100% of the time?

Still, I wish, she had used her influence to make a dire situation better. She was the only one, that could send Meredith back to the Gallows 'like a good girl' (I think, those were Elthinas words?). And to make the templars not punish Orsino for speaking out in public. She should have used that influence, she still had to try to make peace between mages and templars. Nobody knew by that time, that Meredith was under the influence of the idol and even with the idol, she still obviously respected Elthina.
I know, the game has to have a neutral Elthina, but tbh, it would have been better, if Mother Petrice had just assassinated Elthina and became the new grand cleric - and totally in line with Meredith. The end result would have been the same, but more believable storywise. No one would have even tried to argue with Petrice about mage rights, seeing what a hard liner she is, thus making room for the mage rebellion. Don't know, but it seemed a wasted opportunity since Petrice was a great adversary tbh and imo even a better one than Meredith.

Too bad she didn't use that to make Meredith obey the laws she was supposed to be enforcing.

It's also worth noting that even the supposedly pro-mage Justinia is never shown having a problem with Meredith usurping the Viscount's office like that, and there's no way she didn't know about it considering how closely the Chantry was watching Kirkwall.

Indeed the only time as I understand their rules that templars are allowed to take action without permission is if a mage is possessed and has become an abomination such as if they fail their harrowing. And I think they're only alloewd t od othat as a containing the problem cenario to prevent the situartion spreading out of control such as what hapened in the Ferelden circle during DAO the only problem there was I think for the templars in that scenario was it kind of spread so quickly that they couldn't control it so a complete Anulment was potentially necessary there. I say potentially as I think it's likely he'd have got permission to carry it out So in that sense in Gregoir's case he was right to ask for permission to do it because he was following the rules he and his fellow templars are sworn to follow even though it wasn't required in the end thanks to the warden. Meredith on the other hand was not justified in what she was doing though her mind had gone cuckoo thanks to the red lyrium.

With that being said, she did have a point when she called for the Gallows to be searched top to bottom.
I replayed the Annulment tonight, siding with the Templars, and as soon I entered, I was knee deep in blood mages and demons who completely ignored all the mages around to make a beeline for me.

Now, I'm not saying that there were definitely blood mages hiding amidst the Circle's population...but this really is a LOT of demons and blood mages for a Circle supposedly free of corruption.

I agree with Meredith that the tower should have been searched and checked and in the en dbefore the final battle didn' tOrsino offer to help Meredith do just that? It ma yhave been a while sinc eI last played DA2 but I do remember Orsino''s offer to help her check

H ewasn't the ringleaderhe only used Blood magic himself because he was getting desperate and knew Meredith was going to kill him anyway.