Cubical sites as Eilenberg-Zilber categories

We show that various cube categories (without diagonals, but with symmetries / connections / reversals) are Eilenberg-Zilber categories. This generalizes a result of Isaacson for one particular cubical site. Our method does not involve direct verification of any absolute pushout diagrams. While we are at it, we record some folklore descriptions of cube categories with diagonals and determine exactly which of these are EZ categories. Beforehand, we develop some general theory of Eilenberg-Zilber categories. We show that a mild generalization of the EZ categories of Berger and Moerdijk are in fact characterized (among a broad class of ``generalized Reedy categories") by the satisfaction of the Eilenberg-Zilber lemma, generalizing a theorem of Bergner and Rezk in the strict Reedy case. We also introduce a mild strengthening of Cisinski's notion of a \emph{catégorie squelettique}, and show that any such category satisfies the Eilenberg-Zilber lemma. It is this tool which allows us to avoid checking absolute pushouts by hand.