SEVEN's main base seems all nice and luvvy-duvvey but, unlike Unlce Vlen, you do get to see the inside of his head and that's not a nice place to be. So he's out.
Grandfather....less sure. On the one hand he seems to have the best attitude towards the younger races, but on the other he does have a tendancy to meddle, and how he'd change when (if) he was the last one left is difficult to predict. Tempted to shoot him.
Of course you don't know that his archive is destroyed.
It's a fair bet that it was because whilst the place may have been a trap it was prepared as a trap whilst SEVEN was outside (so it couldn't have been relocated out) - it was found kind of by accident, so there'd be no reason to have relocated it.
Can't see him really bothering with vengeance. Dispassionately noting that you know too much and having you taken out as a loose end, maybe - but I can imagine him doing that post campaign anyway.
Probably wouldn't shoot him, more as an insurance policy against any other sons or leftover hegemonizing swarm weapons systems.