Something very logical and that no one has mentioned yet is the great possibility of them playing at least one song of SDoIT, giving the ocassion of its 15th anniversary.. When it was SFaM's 15th anniversary they actually played 4 songs from it in the encore.. My guess is they'll play more than one song, and the same goes to FII, that resembles the case of Awake (20th annyversary) of which they actually played half of the album..
Anyway, I think they don't have much more room than playing two or three songs at most from each of those albums, because the main celebration is I&W.. But even so, I think they will -or should- be playing songs from SDoIT, and one of those could definitely be TGP... since this one totally matches the "monster song" description..