Gula from the Lost Page said:
Version 1:
"Unable to permit disharmony,
you will be disappointed by fate,
and lose sight of true strength...
Misreading the truth,
you will venture forth in secrecy..."
Version 2:
"Imbalance observed, strength misplaced, a future filled with sorrow.
Words of truth misunderstood as they explore the secret of tomorrow.
With a single strike, toll the bells and herald the end, bringing war upon us, as fate did intend."
By comparing the original translation of the Lost Page to the released version, we can see the correlation between the passages. When analyzed next to the actions of those considered traitors, it should be easy to extrapolate. Square is trying to throw curve balls and have us think it's Luxu, when it's clear from the original translation that it's referring to Ava.
Green text:
In Version 1, it is clear that it was Ava. By the time Gula revealed this to the Player, the other Foretellers had already come to accept that war was inevitable.
Version 2 muddies it with the specific words chosen. Because during the events of KHx, Luxu was observing imbalance and disharmony between the Unions. He was already aware of what the future held - and understood war brought sorrow.
Luxu doesn't care about stopping the Keyblade War. Ava does.
Purple text:
Version 1 says that "you" will be disappointed by fate. Once again, check mark for Ava. When she confronts Luxu, he tells her what's going to happen and she rejects what she hears. She literally cannot even.
Version 2 could be interpreted a couple of different ways. I only highlighted the part of the sentence that directly correlates to the passage in Version 1, but if the whole passage is selected, this directly points to Ava; eliminating Luxu from being the traitor because Ava
shot struck first.
Yellow text:
Version 1 specifically states Ava's downfall. she put her trust in the Union Leaders and strength in numbers. While she was doing what the Master told her, she was doing it out of fear of the events to come.
Version 2 is kind of vague. No clear indicator of who the page is referring to. This is intentional. This was designed to keep us and the Foretellers off of Ava's trail.
Red text:
Version 1 could apply to both Luxu and Ava. Both of them are fulfilling their role; going about things they believe to be true. Ava, however, is the one that believes Luxu is contorting the Master's words to fit his beliefs.
We see at the end of KH3 that Luxu has been fulfilling his role, while Ava is somewhere dicking around. She refuses to come back. Luxu probably wouldn't hold it against her as she was doing what she thought was right, but she doesn't understand that he was just fulfilling his role. None of the other Foretellers believe Luxu at first, but he takes time to get them to understand, which is where the game ends unfortunately. This is just a side note. Comparing who is and who isn't doing the things that the traitor is doing.
Version 2 is once again not so different that it could lead to a different analysis of the passage. This is 4 checkmarks out of 5 for Ava being the traitor.
Blue text:
Version 1 is also a little hazy; because while this seemingly applies to Luxu, he's not keeping secrets from the other Foretellers (if one asks. Ava did). He's simply sitting back until the war and then moving off on his mission, which isn't secret. Hell, we know this, so it can't be that much of a secret to him. Contrast this to Ava, where she is moving in silence. No one has seen or heard from her since the Age of Fairy tales. Her role has been fulfilled, and as far as she believes, Luxu is the traitor. [She may possibly know it's her and feels too ashamed to return when summoned.]
Version 2 sounds like time travel. Plain and simple. As far as we know, Ava can't time travel. She has knowledge of Data World Travel, that's about it. That sounds like Luxu, but once again it's something that could be interpreted a certain way.
Given this, Ava is 5/5 for being the traitor, while this would technically put Luxu at 2/5. So going by what Gula tells us about the Traitor and The Lost Page, it's undeniably Ava.