The description of the location of the VSS according to the service manual, is "Rear center of engine compartment, mounted on transaxle." I'm only aware of one VSS on the 1996. There are other speed sensors, such as shaft speed sensors and turbine speed sensor within the transmission, but those would not be considered a VSS.
For the P0500 diagnostic code, the service manual has a rather interesting note in the diagnostic subroutine:
"Note: Delayed engagement or no vehicle movement may be caused by a transmission concern. Harsh shifts and/or erratic speedometer may be caused by a failed speedometer or an open or intermittent ground within the instrument panel on vehicles with electronic readout."
Per this note, your issues could actually be due to a bad speedometer rather than a bad VSS. I suppose one way to test this theory could be to disconnect the cable from the VSS and leave the electrical connection on the VSS to see if the transmission shift concerns improve.
-Rod