chorizo ? Which style to use? Spanish or Mexican?

I agree. It reads "ground chorizo". Spanish is the cured version.

I suspect the Mexican chorizo: it is the kind that I can usually find in a local bodega, and which comports with the recipe description of a meat within a casing that can be easily crumbled -- or at least it isn't a more solid log sausage, which is what I understand a Spanish chorizo to be. But if you can find Spanish chorizo that can be easily broken up or crumbled after removal of the casing, then I presume that would work as well.