Since I can't figure out any way to neuralyze the whole of Pandora(even if you neuralized every lifeform on it, Eywa herself lacks eyes.): I'd recommend that you'd simply take advantage of the situation and do the unthinkable: Tell Eywa the truth. Tell them of the Suvian threat, and why you had to kill that beautiful, perfect, sweet, defenseless little Mary-Sue. Since you'd have to have them aware of the PPC, you'd better take advantage of it.

And if you did decide to neuralize Pandora somehow, I'd recommend starting with an orbital platform with a really big neuralyzer taped to it, hanging directly above the nightside of Pandora. Keep orbiting in synch with the nightside, and neuralize the whole of the planet over a 24-hour period.

First, a planet-wide exorcism has been done before (twice, I think), though I don't know about a neuralization. I suppose it would be possible, but you may need some help.

Second, there is the fact that in general, the canon environment protects agents because it knows that they are here to help. You could extend that to Eywa, as sort-of-a-character who the PPC wouldn't mind having on their side. I would suggest having Eywa's awareness be part of the effect of canon protecting the agents.

*facepalm* Of course there is.

Aren't there some canon characters that know about Mary Sues and PPC? Maybe the central consciousness, if there is one (I don't really remember from the movie.) could know about Mary Sues?

You're right; that would be interesting.

I'd say that once you got rid of the Sue it should snap back into forgetting all that.

Since that's what is intended to happen once the Sue is deadified, the canon snaps back to normal...

Ooh...I don't know.

How would you even go about neuralyzing the thing? You can't exorcise it, because it doesn't sound like he was under the influence of a posession sue. Maybe if you connected somebody to the Big Ol' Treebrain through their convenient neural hair-tentacle, and then neuralized it... no. You'd have to neuralize every eye-posesssing lifeform on the planet, and... no, that wouldn't work, because Eywa clearly stores data in her neural network...

The difficulties and/or impossibilities of neuralyzing the planet may make it unavoidable to have the entire planet aware of the PPC. But equally, having an entire canon aware of the PPC would (probably) be really bad. (but admittedly interesting.) Either way, the Sunflower is going to administer serious pain in a you-ward direction.

Nice to see somebody else who saw Avatar.