Did Elthina do the right thing by staying neutral?

Tranquilizations cannot be done without the Knight-Commander's permission. They're also supposed to need the First Enchanter's permission, but they were already ignoring that part. Anders praised Meredith for not going with the idea of making all mages Tranquil. She was still using it illegally and disproportionately. We know Maddox had already been made Tranquil at that point because it's the same incident that got Samson expelled from the Order.

Yeah it's like Orsino said it was getting to the point wher a mage couldn't sneeze without being accused of corruption. 

And Meredith didn't even notice the new Tranquils... Nobody noticed... nobody warned her...
No. She supported Alrik, like MANY Templars in the Circle. Hawke killed many of them, in the Chantry, and in the secret tunnel. In the secret tunnel, they saw and heard what he was planning, and did not stop him, but they fought for him, to be able to do so. They supported him, they were able to die for him and for his crimes. How many Templars were with the same "values" in her Circle? It sure, Meredith knew everything.

Also... Maddox.

Never said they were. I was just saying that Alric was doing it illegally without said powers that be like Meredith knowing.

That's unbelievable. And if this true, that's even worse: the mages' life didn't matter anything for anyone. They weren't even a number, if she didn't know about them.

Cullen in the Inquisition confirmed, that Meredith (herself) tanquilized mages for lesser "sins" that Maddox's was (a love letter). Cullen is a liar? Or just made joke?

For the mages, it's justified. Meredith herself justified them. The Chantry justified them. Cullen himself confirmed in the Inquisition, Meredith was a criminal, when he said, he Tranquilized mages for lesser "sins" than a love letter. Also: YOU mentioned the demons.

And you can agree with the Annulment. Innocent children's massacre by a perverted "right". 

I spoke about those lines, yes. I saw the scene not once. The best of it: he didn't (necessarily) lied. The game is intentionally vague here, to justify every view here.
And I still think, he didn't lie here. Because of his characterization fits my explanation, and doesn't fit anything else. Such a man, like he –according to his backstory + everything we saw about him before–, can be a fool, can make mistakes (big ones), but not such an "I-was-cheating-you-from-the-beginning" villain-type. And tell me, why he would lie here? What would his reason to lie?

Bethany's reaction was justifiable here, just like Hawke's. But that doesn't make true, that he knows about his madness when there are possibilities to prevent that. 

But the most beautiful in this: Whatever Orsino did or not: Meredith can't be right. Never, for a little moment. Meredith was never justified, not even in Act1. (And not even according to the Chantry's perverted law.)

There can be no peace.

"He was clever" is a very cheap explanation about that personality change, what needs to this.
He has reason to not tell anyone, when it was already late – and I believe it was late, and he didn't know about Quentin's mental state until it was late. I already said, why I think that, and the game allows it. 
I also know the letter. Again: nothing about that discovery what Quentin achieved. Nothing about the zombie bride. And the Harvester as conception also very impressive. But again: seems it's irreversible, then Orsino was not able to practice – not mentioned, how he's able to gain corpses? He just go out of the Circle, and go back with 10-20 corpses? Or kills the mages in the Circle? (True, nobody noticed the new Tranquils, as Hanako pointed on that, because seems nobody cared about some mages... so: perhaps, Orsino killed the mages to play with their corpses, yes? Nobody would notice one-two-ten-twenty... or more mages..., ONLY, if they escape. Fun stuff...)
What Bethany think about it at the moment, not a proof. 

Again, the game allows you believe, he knew about everything, and he's the mastermind at shows him caring, good person while he's a moustache-twirling evil – and also allows me to think, he didn't know about Quentin's mental state until it was late and didn't know about his real experiments, and he's just a real caring man, who's able to make great mistakes.

Meredith can figure out some things, she was not stupid... but she never can be right. But whatever: she and her kind, can never be justified. Tragic villain – still a victim of the system, but also aggressor, and abuses her power in the system.

The best thing about Orsino again: not really matters what he did: he's not the "mages", while at the moment Meredith's the Templars. Because of their status in this game.

Which annoys me and my reason to insist on my theory, that Orsino's personality, behaviour and background. Simply the end can not be explained in another way. Without it, I wouldn't mind. He does not really affect my choice. He's simply no matter – just a senior-prisoner. But a senior prisoner, who tried to convince his people, that the suicide isn't a solution. This is why he took the position when nobody wanted under Meredith's terror.

1. Yes, I listen him, and he didn't say anything what wouldn't fit my explanation. 
2. What Bethany said, isn't proof for anything. A possible outcome, as she thought. But she didn't know everything either.
3. About he used the Harvester: yes, he's an experienced mage, Meredith was not right about, he should practice that kind of magic. It was a desperate try. Of course, it doesn't come from nothing: Orsino was very educated. The Circle trained him... And just remember: he sent Quentin CIRCLE books, from the CIRCLE's library.
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4. Orsino's not the mages, because the mages are individual civilians. If he's "the mages", then any random people in Kirkwall, who committed any sin/mistake, is "Kirkwall people", then Kirkwall people should be punished, collectively?
But Meredith and the Templars aren't individual in this situation. The Templars are an army, an Order, and they obeyed to Meredith. So: Meredith is the Templars.
That's not some unfair double standard, but come from their POSITION.