One or even two changes are kind of possible indeed. I mean, I wouldn't be shocked if they don't change anything at all, but TETMD for The Clairvoyant does sound plausible. Children of the Damned would kinda fit there if they'd want to drop The Wicker Man and Bruce does like that one quite a lot, but it would slow the set down a bit too much. And they seem to love playing The Wicker Man and it's one of those post-reunion songs which has earned the status of a modern classic and it does get the crowd going... So while The Wicker Man is one of the easier songs to replace, when it comes to theatrics and all, it's hard to find any suitable replacement without messing up the setlist order or pace too much. Powerslave would kinda fit anywhere to the later part of the set, but I don't see it making an appearance... As for the rest of the songs, Heaven Can Wait has been mentioned here often and while it does fit the theme(s), I seriously doubt it. And to be honest, I'm ok with them keeping it out of this show.
So, in the end, there are only a handful of plausible replacements for one or two songs and a couple of those seem already problematic when thinking about the flow and pace of the set, which they totally nailed this year, so yeah... we'll see. Changing Hallowed and FOTD around and replacing TETMD or some other song of that nature would work relatively well, but I guess the setlist order is pretty much set in stone now and since they already moved FOTD from it's traditional position for this year, I doubt they'll toy with it anymore during this run.
So, there just isn't that many plausible options, but if they somehow end up doing SIASL, I'll gladly apologize my seemingly overflowing negativity.