"Fat" is probably the only song on the setlist that I can't see leaving EVER. It's such a classic and it makes such an awesome finale! "Amish Paradise" on the other hand is already a very old performance. It's basically Al walking back and forth singing the song in a costume. Much like "Bedrock Anthem," which got the axe last time around. I prefer the performances that have more of an "act" to them, such as LAS, "Fat," and OMM.
Anyway, aren't we like WAAAAAY off topic right now? I think it's almost inevitable that Al will parody Taylor Hicks' performance style in concert. Think about it. "American Idol" performances are probably the most widely viewed musical performances ever. More people have seen Taylor Hicks perform MULTIPLE TIMES than have seen Green Day, Chamillionaire, Usher, or R. Kelly perform even once. And Taylor has schtick that's just begging to be made fun of.
I think this song will be performed in its entirety, along with "White and Nerdy" and "Canadian Idiot." If not, then I fully expect that it'll at least be in the medley, and that Al will have a gray wig, a harmonica, and a suit for that portion of the medley.