I need more to go on, than the Inquisition's acting dodgy, go with it.
Not being able to consult with all involved properly, leaves it me in the position of having to trust where I left my IQ and it's people at the end of DAI, thus making me have to trust their word over Teagan's, regardless of what evidence is given to the contrary. I'm just stubborn that way.
I was a bit more specific than "the Inquisition's acting dodgy, go with it," if you'll recall. I specifically pointed out that Josephine implies she's been dodging politicians for a while, and that while she only states she's been dodging Orlesian politicians she also states that Ferelden's are more dangerous to them. I also pointed out that they show a shocking lack of political tact in the DLC itself. This does not point to the Inquisition being worthy the trust you place in them to have acted tactfully in the past, and the results don't speak to it being worthy of Ferelden trusting it to do much of anything.
I suppose it is okay (though not optimal) that you're going with this interpretation despite all the evidence (or perhaps I should say such evidence as there is) being against it, but I do wish you'd admitted that that's how it's going to be a while ago. It might have saved us some effort.
Well put. There is too little information on those two years, and for all we know this whole thing was contrived to get rid of a rival / threat.
A lot of the evidence I cited is the Inquisition's own actions. Unless you assume Teagan is a secret maleficar or has one under his control (or is under the control of one) he can't contrive that, and if he did there's got to be a simpler way he could have used that power to achieve his ends. Manipulate Cyril in order to sabotage his efforts to manipulate the Inquisition, maybe? Or just put suggestions into the Inquisition's heads to make them hear anything Teagan says as shockingly reasonable and worthy of more than ten seconds consideration? That might actually achieve something more advantageous than the Inquisition disbanding, if Teagan really wants to have some fun.
Not to mention that you'd expect Teagan or whoever's using that power to investigate when the Inquisitor walks out (because a manipulative Teagan or the boss of a manipulated one would see it as a serious red flag rather than the calculated insult Teagan to all appearances mistakes it for) and use their power as a weapon against the Qunari... which doesn't seem to have happened. Yes, maintaining cover is important, but the Qunari change things and no sane mage wants them anywhere nearby.
Oh, and if he was using such power he'd have to be able to slip it by any Divine Victoria. One is a veteran spy (albeit a sloppy one sometimes) one is a mage, and one is the setting's version of a witchhunter. Assuming that nothing is wrong apart from the Inquisition acting dodgy is a lot simpler than assuming Teagan's either manipulating events or the pawn of someone who is, and that the mastermind not only got away with it but possibly achieved their goals.