I think this tactic is flawed, Pirates have sisge frigates in the gravity well, right? so the moment you colonize it, they will turn on "their" base.
I'm not sure on this one. I know all other colonizable planets always have at least one siege frigate, but I'm not sure about the pirate base. I know they can have pillagers, but I'm not sure if they always do. In any case, like all siege frigates, a few carriers can pop in and remove them before the rest of the defenders actually close in.
I think Blair is wrong on this one, to the best of my knowledge Pirates disregard culture (they are always at 25%).
IIRC, you cannot even target a pirate base directly with a deliverance engine because it doesn't have population. Maybe I'm confusing it with uncolonized planets, but I seem to recall being unable to use my deliverance on a pirate base. Unless deliverance culture is somehow different from regular culture, it won't "defeat" the pirate base, either.