Mwahaha, yes! I told you it was nasty, and it's REALLY nasty. Not gonna spoil TOO much but it involves illusions, and trapping her with no escape (until Matt, Roan and/or Bol manage to help her get out) and is waaaaaayyy better than the PTSD/nightmares angle I was gonna go for for that plot point originally (though, of course, it may lead to some form of minor PTSD as a side effect anyway which could be pretty good for them as a development point in and of itself where she basically can't/refuses to sleep properly at night without Yerbol in the room with her because he's the only thing (sans maaaybeee Roan, but as much as he cares for her he's not gonna let her stay with him at night at twenty years old cause y'know, he's still a badass Sith Lord and they don't do that lol) that keeps the flashback/nightmare of that event away which could be quite fluffy and adorable if a little bit cheesy XD)

Yeah, or at least I'm THINKING about killing him off from a character progression point of view for Ari herself and also to develop Ari/Bol's relationship more...cause otherwise it could be difficult to move past the "Daddy disapproves of this entire shenanigan and even though Ari WANTS it to be a thing, she's a daddy's girl and wouldn't want to incur his disappointment" thing XD 
It would ultimately end with him finally accepting/approving the whole thing on his deathbed, cause I kind of thought he would have this thing (being a stickler for the whole "Jedi suck/are weak/I hate them" viewpoint despite everything that they've been through at this point) where he basically NEVER refers to Yerbol by name and either just calls him "(The) Boy"/"Kid" or "Jedi", up until the moment he tells Bol and Neta to take Ari and the others and run (perhaps he has some kind of premonition vision and knows he has to kick it if they're gonna win) where he finally ACTUALLY calls him "Yerbol" O: Though if it works out differently when we actually get there and I can't bear to kill him off (I like him too XD) then I'll figure out some way for him to come to terms with it and remain alive (can you imagine the kind of grandpa he'd be? omg! XD)

ooohhh, I like the idea of an information warfare thing, yeah! 
And as far as Yerbol accompanying her to take out Bracknell that's good on my end too, I can't see him letting her go on her own especially since by then he'd know she was livid enough to only be thinking about actually killing him and not being sensible enough to avoid getting HERSELF injured at the same time xDD
And as far as building up to that end point goes that sounds good too. (and they DEFINITELY deserve some time off after all that, poor dears! Where they can just be them and not worry about saving the galaxy, maybe that's when they can hit Taris and find Bol's parents and visit with them a while, perhaps? ouo)

EDIT: Also on a slightly unrelated note to all this epic big plot stuff, love the image you have for Bol there now. It suits him :P