Possibly. I'm not sure I buy it. That line seems to reference the existence of at least one prophesy that the Inchoroi care about that we have not even heard of. I kind of think it suggests the existence of numerous prophesy's that the Inchoroi follow and we have never heard of.
Also a possibility. My understanding is in no way confirmed.
There are areas where you can make comments about the way time has become tangled up. You could draw a time weirdness map of the books and it would not be identical to a standard map of the events depicted. The additional information that would appear in the time weirdness map makes questions like primacy relevant.
Not from the metaphysical perspective, no. Since in Earwa powerful agencies are active simultaneously all throughout time, its non-linearity from the point of view of mortals is a given. I believe you refer, at least in part, to the events beyond the scope of the Gods' vision. Like the failure of the first White-Luck Warrior, which in retrospect created Sorweel
before said failure. But the moment the change of the eternal transpired, Yatwer always knew her first vessel was going to fail, yet at the same time the vessel already existed, so it has always existed and been part of Yatwer's plan. Nonetheless, since it wasn't sufficient to deal with Kellhus, her plan now included a second vessel. Of course, for her it was always so.
So there can't be more than one inside then?
That depends. Since the context of the Outside is intrinsically connected to the context of the Inside, and the absence of time is the absence of space the way we understand it (speed of traveling is a function of time, so without time there is merely untraversable distance/difference between concepts, if you will), I'm inclined to consider the Outside uniform throughout the universe and the same as it is in Earwa. If there were other Gods, or if the Gods were different for other races, Men would encounter it in their interaction with them, because the Gods are unchanging, eternal. Since we know the Gods only as human Gods (for example, they don't seem to have that high of an opinion about Nonmen), I believe this is their only nature. In essence, that's what makes Earwa special: it shapes the Outside and is in turn shaped by the Outside, thus creating a feedback loop that imposes Earwan rules on the universe.
So, could there be, for example, other dimensions? Sure, but that wouldn't be very relevant for the rules of the story, just like other planets weren't relevant. Earwa is where the shaping happens. That's why the No-God must rise there, among other things.
I've always thought of the inside as a just a bubble created by the gods in the outside.
Now this is a strange notion. The Gods didn't create anything, the God of Gods did, which is a separate entity that we know almost nothing about.