Which comes first firm flex or stiff flex in a shaft?

Answer 1

There's no "firm" answer (yuk, yuk!). Shafts stiffness is specified by the manufacturer, so there's no objective determinant of what's stiff, firm, regular, or whatever. Typically, players with normal swing speeds will use R (Regular) shafts, while faster swingers will go for stiffer ones, but that's no guarantee, just the way to bet.