Would this mean that it would retcon the Omega audio story out of existence? Seeing as how Omega returned to the anti-matter universe and all.
Also, I agree about that the potential retconning of the Tenth Doctor's lifespan would be irritating, seeing as how he's earned his exit in the manner that he did. I have a feeling, supposing any of this is true (and I think this part is, by far, the most improbable), this might've been intended for Eccleston's Doctor - or maybe Eccleston would've been both Nine and pseudo-Nine? Like, pseudo-Nine starts the story, then just before Omega's revealed, the real Ninth Doctor appears to the story through him absorbing the Time Vortex at the end of Parting of the Ways? Sounds crazy, I know.
Still, while its semi-plausible, I'm not really sure this is what we'll see. Seems to derive too much from Arc of Infinity (and consequently The Three Doctors) and Mawdryn Undead, where the said solution is revealed - and that makes little sense because the Doctors have, well, saluted themselves before.
Still, the part with the paintings could have some basis... Reasonable excuse to run clips from the whole of the show.