Lets be real here. Tevinter is not intrested in the southern mages. Alexious was intrested in the inquisitor and nothing else.
We know that. There's no particular reason Fiona would.
People in the real world can't be expected to assume that they're dealing with moustache twirling villains. The offer presented to Fiona wasn't as ridiculously bad as people in this thread want to represent it. Though accepting it was still a dumb move.
The latter point here is a good answer to the first, but I do have something to add. I believe that Tevinter itself would actually be interested in southern mages. The way I see it, the they've been at war with the Qunari...forever, which means they could always use more people to increase its population. And as I pointed out in my last post, Tevinter is not completely evil. I can't stress that point enough. They do lots of evil things, yes, without a doubt, but their whole society alone is not evil. Considering the rest of Thedas binds mages (literally, in terms of the Qunari), the Imperium just reverses roles, where the non-mages are the ones greatly oppressed [though for complete disclosure, it must be pointed out that a significant portion of the mages in the Imperium are opperssed as well, but in a different way, and that way is much more akin to the Roman Empire and its people (which Tevinter is based off of), which I'm not going to get into details of here], and mages have control.
Technically it was Lambert who started the war by interrupting a meeting sanctioned by the Divine without the Divine's authority (despite the Divine agreeing to his demands prior to the meeting). All she did in said meeting was call for a vote on independence (which was within her right) - a vote which almost certainly would have been defeated anyway due to the Libertarians' failure to enlist Wynne's support. When Lambert was directly opposing the Divine, Justinia threw her support behind the mages of the White Spire in order to prevent the Seeker/Templar coup. Fiona then called for a second vote for independence, and considering the alternative would have been death or tranquillity for most of the mages, their support for independence was justified IMO (even though I do not support full independence for the circles).
This is almost a completely true statement, and I'm glad someone brought it up, because it had not been mentioned previously. However, you made a small error in that it's actually the a second and third vote for independence. Prior to the meeting in the White Spire, which Lambert interrupted, there was a vote a year earlier, where Wynne was and voted against, resulting in the vote failing, and leading to the disbanding of the College of Enchanters until that meeting.
Yeah, Morrigan says the exact same thing if your Warden romanced her regarding Fiona and Avernus and the Calling. Which just made it more frustrating since Fiona is in the same damn building but Morrigan is acting like she's not even in the same place. Come on.
Good point, which is part of the problem I have with Fiona's lack of involvement once you finish In Hushed Whispers. I said before I wish they had made more use of her other than a couple comments when the story moved along. Although Fiona doesn't know exactly what removed the taint from her, because there was a lot of crazy stuff that went on in The Calling that would be impossible to reproduce exactly, especially if you killed The Architect (like I did in the Keep, though I didn't do it in my playthrough because I didn't know what The Architect's plan actually, having not read The Calling until after). The best you could get out of Fiona was a description of what happened, and they could try and replicate the brooches used I suppose, but it would be challenging. Not to mention I believe the Wardens studied her to figure out what happened but couldn't, though I may be wrong about that. I know they tried to put her through the Joining again.