Well that isn't really something you can say though is it? Any action no matter how small can change the future. I'd say the minute Jacen had the vision of Allana and set himself on his course he was already changing the future, at least the future he'd seen, because he was setting out to specifically prevent that event from occuring. This of course leads to things happening that probably wouldn't have happened if he hadn't had that vision, as that vision is the major reason for his change in personality. If you wanted to pin it down to a single thing that would've led to Abeloth being released, then it was inevitably Jacen having that vision of Allana (Based on how events played out, as its hard to argue what ifs in terms of what might've happened) because everything he did from that point on was based around that vision. So the vision was the catalyst through which the future was effected. If Jacen hadn't had that vision, there would've been no reason for him to take any of the actions he did (unless of course the writers had presented him with another reason, such as Tenal Ka dying or something) You see what i'm saying? I'm disregarding what ifs and just looking at what actually happened, and in that sense I believe that's how you'd explain Jacen being the cause of Abeloth's release. That having the vision of the future, and steadfastly deciding to do everything you can to change it, already changed it to some extent. That at that moment, Jacen of course couldn't tell, but the future had already changed and his path was already set out before him. Everything he was going to do, had already happened in the future. I understand what you're saying however, that the Mindwalkers are like when Lumiya told Jacen about Vergere being a Sith. Very dubious at best, and with unknown motives and intentions. And remember Abeloth was never freed before becuase of Cenerpoint.