off hand I can say that VIRGIN, SIMS, A NECESSARY END, and MIDNIGHT MASS can't be. They involve world-changing events or developments that can't be accommodated by the Secret History. Many of the others could be part of the Secret History milieu but they're too tangential and don't contribute to the history so it seems superfluous to list them.
FPW
FAQ
"It means 'Ask the next question.' Ask the next question, and the one that follows that, and the one that follows that. It's the symbol of everything humanity has ever created." Theodore Sturgeon.