I have Voice 4 set to Mod Type Pressure, and Voice 3 set to Mod Type Velocity. If I play and Hold a note on 4, with the velo/mod output going to a filter, then switch to voice 3 and play a note then apply aftertouch, it opens the filter - voice 3 is not going through the same filter, in fact the velo/mod on voice 3 is not connected at all. So it seems like the pressure/aftertouch is global across all voices, not just the selected one. The manual says that the outputs are all independent.
