Pre-destination in Thedas

There's also that statue in the circle, or person turned to stone more than statue, who seemed to see either Cory or Solas coming about.

If we are talking about dreams and visions, Kordillus Drakon was supposed to have had a vision (before becoming Emperor), which ended up being recorded as the Canticle of Exhalations:

dragonage.wikia.com/wiki/Chant_of_Light_Verses#Canticle_of_Exaltations

I think I recall someone a few years back, may be one of the Devs, saying that they were spirits imprinted with the memories of those people. A bit like when Solas went to Ostagar and saw both viewpoints of Loghain's actions or the spirit of Justinia in the Fade. That wasn't really Justinia. If it was you'd be really worried why she hadn't passed to the Maker's side by the time we got there.

As for ghosts being against Chantry teaching, well neither Cassandra in the Fade, nor Leliana out of it seemed bothered by the idea that it really could be Justinia, in spite of Chantry teaching on the matter. I guess some Chantry stalwarts would freak out at the Gauntlet and others would be moved by faith. Luckily we only had Leliana with us and she had her own unique view of things anyway in those days.

Obviously the only way you know if a vision of the future is genuine is if the person tells you about it and then it happens exactly that way, with you not being able to control the outcome through your knowledge.

There is also a difference between someone like Brona or Sandal who just claim to have seen something in the future, like watching a video, and Drakon would also claimed to have heard the voice of Andraste instructing him to do something. He was specifically be thinking he should be taking action in order to bring that about, since it was a prophesy of the Maker's return.   In Brona's case it would seem it was a premonition that she was unable to act on to prevent, which is why she laments her situation.

Incidentally, as I have posted elsewhere, I don't think Drakon's vision was a genuine revelation and thus any actions that he subsequently took as a result were not by Divine decree but simply his own ambition. I don't doubt he believed it was genuine; the mind can play wonderful tricks when you want something enough and in Thedas we also have the problem of spirits playing mind games with people but it sure as hell didn't come from the Maker or Andraste.

That of course is entirely my own faith on the matter and that of my PCs but then I've never believed the Chantry truly represented Andraste and the Maker ever since DAO. Subsequent events and discoveries have only confirmed me in my view. I would very much like the opportunity one of these days to be able to state in game that I believe in the Maker and Andraste but I denounce the Chantry as a fraud.

Actually I've been looking again at the entry on Eleni Zinovia and note that it says that few outside of somniari can see the future with any degree of success, which implies that somniari can do this.

However, although the person writing that, from Perivantium in Tevinter, believed that Darinius was one such somniari who could see the future, elsewhere in his entry it states that actually this was because of his effective network of animal and bird spies, who were able to give him information that enabled him to out move his rivals in such a way that people thought he could predict the future. Naturally Darinius wouldn't have wanted to disabuse them of this idea because it would add to the awe in which he was held, but in fact his powers of prediction had a wholly mundane explanation.

So it is not clear whether people are actually able to predict the future or whether it is just the superstitious belief of others than they can do so. In fact they are either using spies, as Darinius did, or possibly spirits from the Fade to assist them. Zinovia definitely seems to have got her premonitions from dreams, so likely Fade spirits.

If it is just a general dream, this seems fair enough, but when a person declares this is a Divine revelation that approves or encourages their action in some way, then I become very wary. In Drakon's case we will only know if it was correct if the world does end in the way he describes. Otherwise we only have his word for it that it was genuinely a vision from the Maker/Andraste.