Ahhh I'm SO glad I'm not the only one who did a double take @ SoR ....that whole arc was just...nurp. Sooooo not Revan -__- After Meetra's death, however, I can totally see him going into more of an unstable "oh, this bastards gonna die and I don't care how but I'm gonna kill him" sort of mental state :K 

Regarding Vano leaving the Qyaari worlds, I'd imagine she'd have taken on an apprentice (or several?) at this point to help her with the no doubt massive archive that the Qyaari now have XD so she could plausibly make up some sort of excuse eg. Going to Quensu to continue searching for an artefact and then slipping off to find Aria and Yerbol and what have you once shes not being watched as closely....OR I suppose Vitiate is powerful enough to teleport her someplace idk, I'm kinda inclined to go with option 1 cause it makes more sense (or a third option, if ya have a better one XD)

Yes to all the middle points!:D Hehehe I feel like Vitiate possessing or perhaps just influencing, since she's cooky enough already right LOL, Vaylin to kill Meetra in order to destabilize Revan would be a solid enough plan on his part? :)

As far as the "ending" goes I 100% agree with you on the father thing (hence the ??s Haha XD) , I think our duo are world-wise (and powerful) enough to come up with a solution themselves by now without some ancient entity's help? XD 
I dunno WHAT just yet but, we got time to think of it Haha XD 
Perhaps something along the lines of Vano/Vitiate kills either Vaylin or Arcann, Revan kills the other and just as they think they've won Vano "snaps" and reveals shes really Vitiate and que big fight where they try to kill Vitiate without killing Vano etc.

(and either Revan or Vano or both, could potentially die here too, depending on how mean we want to be to Aria and Yerbol at that point - also feel like Revan would suit a hero's death at this point? I can't see him successfully grafting himself back into the changed society all too well after he's essentially lost the last part of his old life when Meetra dies, it more feels to me like he would be done at that point, BUT he'd go down fighting and making sure Vitiate is never going to hurt anyone again?)
Thoughts? Bwahahaha