If it's not too late XD

Luana Starlight and Orange Plaid will be glad to help if it comes to a major crisis.

Is that the Sue is in ALL the talking animals, every spirit of Nature (Satyr, Dryad, Minor Gods, Naiads, etc). And since those are really all canon characters, we can't exactly destroy them.
The Sue does make reference to her essence as being a power inside of her, which means there is a way to quickly exorcise that number of beings, without a huge exorcising ceremony. It'll also be a way t get her out of the planet, if she merged her essence with it as well.

The answer is the Keyblade, from Kingdom Hearts. At one point, there was a Keyblade created that could unlock hearts, and unleash whatever was in there. Since they also double as weapons, we could unleash, and then slaughter.
Is there any way for the PPC to freeze a planet in time? Otherwise there's a very good chance some Talking Animals possessed by the Sue might make a run for it.

Janus has a nasty temper when it comes To sues who Defile and possess his favored works of lit. He's got a little brother Named Oryx who is pretty dammned good with a sniper rifle if you need long distance assassination after the charges.

This sounds worryingly like the Alumia mission Dafydd and Selene took on- which involved the Sue possessing the entire planet of Arda.

They summoned every single free Agent into the fic to help exorcise her. This situation might be a little different, but I'd suggest a similar operation.