Well.... I didn't believe they existed either, but now I pretty much have to find a way to reason them out so they make sense to me. I doubt Ishamael makes them up now. The one we were given explains too much why as he returned as Moridin he's "wisened up" and stopped making plans that the Shadow's prophecies contradicted. He then accepted Perrin and Mat would fall of the last days only etc. and it is why he's waited until KOD to set the Forsaken on them. Not only he knew it was the right time, but now he knew he stood a real chance.

This also resolves the mystery about Lanfear in TDR. I think we know which book Perrin caught her spying on, and where she was.

So.. where are these prophecies coming from? My best guess now is that they can only come from Darkfriends who have an oracular talent. I think Shai'tan might possibly get glimpses of the future from the Shadow Dreamers and Foretellers, and he can twist these so they reflect his will, his intents. They come true, because Shai'tan extend the power on the Pattern to twist events so what he wishes happen. So, the Shadow prophets basically provide Shai'tan with nexus in the Pattern he sets to attack and alter to his will.

That has occured to me based on a comment by Ishamael at the darkfriend social. He told DF that several nexus points were coming at which events could be twisted their way. He was pretending to be Shai'tan, then. It sounds like Shai'tan really has this power.

The other possibility is that Shai'tan doesn't have control over this, that Shai'tan's touch on these DF foretellers "steals" part of his intents from him and it becomes a "Dark Foretelling". I tend to think it's the former rather than this, however. One thing seems sure to me: these prophecies are way, way too full of over the top praise for Shai'tan, and indications to DF to kiss his feet. Since they don't appear to be pure propaganda invented by Ishamael (and yet... I'm still not 100% convinced) then a direct involvement of Shai'tan in them is a certainty. They reflect what he intends to do.

This all sort of explain the DP in TGH. So, Ishamael expected from it all along that Rand would end up in Falme, one way or another. That explains his lack of interference. This prophecy told Ishamael not much. RJ implied that prophecy was used as a taunt, as for another reason he didn't want to tell us as he might want to use it later down the line It sounds likely we will learn that reason in the next book now.

This also explains why Ishamael laughed at the wolves, and tried to convince Perrin to go back to blacksmithing. And this speaks of him not understanding these prophecies much better than the Light understands the Karaethon Cycle.

All that said, I would say I don't believe these Foretellings are 100% reliable. If they are Shai'tan's wishes and intents, I would think their coming true wholly depends on his success at twisting the Pattern to they happen. This means there must be unsolvable conflicts between DP and the Pattern the Wheel intends to weave.

The one thing I tend to believe will happen in the new DP is that the Hand of Darkness will seize what is His. I think Min had a viewing about this... Shaidar Haran will seize Callandor. The Light will lose the sword. I have this theory why Brandon "spoiled" the solution so early in the finale. It never made any sense to me before, that he would bring it up so soon. What's the point of telling us the sword is the solution at SG, with three channellers etc. That seems to me like a terrible way to handle suspense. But..... my hunch is that it's a complete red herring (actually, it's there to mislead the Shadow... it musn't wonder which sword is meant, nor ponder too much about the three becoming one... Callandor is flawed to fool the Shadow.. the Light doesn't need clues, the Wheel will weave the right path for them) , and it's there for the reason that Brandon wanted to build up our expectations, and make us gasp when the Hand of the Dark steals the sword. Things will then appear blocked, doomed. My feeling is still that the Sword mentionned in the prophecies isn't Callandor at all. It's the new sword that so weirdly came to Rand: Justice. There's something about this sword... in TGS, Rand said LTT knew something about it he was not telling him. Now Rand must know what it is, but he seems to have forgotten... for now. Once he loses Callandor...

The real final sword is that one, and Three becoming one as nothing to do with a trio of channellers. This refers to Mat, Perrin and Rand - the endgame of their colour swirls. All three of them will face Shai'tan together, it isn't Rand alone.