I recall Martin commenting, I think on this exact rumor, that nothing is ever a "done deal" that many years out. The planning doesn't work that way.
I'll believe a TDL Splash retheme when I see it. Wouldn't surprise me if it happens eventually as despite the high GSAT scores the Japanese have zero attachment to SotS characters (want to guess the percent of guests who know the film? It's much less than it was in the U.S., which was already minuscule).
But I certainly hope it's not Duffy, that sounds lame and so many other things in TDS have been taken over by him through the years.