I know from a letter to Morgan Sportes in the 80s that Debord did read Maurice Nadeau, but he mentions only Nadeau’s magazine Les Lettres nouvelles, not the magical history book.
Your contention that the underground surrealists are everywhere except France seems like a good place to start on the project. I offer my assistance and resources, however meager, and eagerly await your findings.
One of these days Frére Dupont will explain the problem of the Mexican jumping bean, and other friends will start on Pierre Menard. Until then…