H-Bridge IC decay modes and MosFET conduction
However, the (overly simplified?) schematic figures in their
  application note SLVA321 (March 2009) all show N-channel FETs and thus
  a conflicting flow of current:


There is no conflict. Look at the characteristic of a "typical" N channel MOSFET: -



Garishly coloured picture taken from here

With no gate voltage you get the red curve that produces reverse conduction due to the internal parasitic diode (circa 0.7 volts) and breakdown at high forward voltage. With gate voltages the MOSFET conducts equally well with negative drain voltages in that area where the parasitic diode won't be significantly conducting.