Will GM 200r4 work with factory floor shift location?
I cant know from experience what will or will not work. What I do know is both ends of the cable and both ends of the cables sheathe will need to be anchored somewhere.
I have to think deleting all of the factory linkage first and starting with a clean slate would be the best plan. Working from the OEM shifter straight down through the floor. Cable sheathe anchored ahead or behind the shifter and ahead or behind the shift lever on the trans, depending on push or pull required. In either case a return spring will be needed opposing the sheathe anchors.
I often take my insight and inspiration from what those engineers much smarter than me have already fingered out. To do this I'll go the pick and pull yards and study various examples. Most everything there today will have a cable operated floor shift.
Attached is pitiful rendition of 2 different cable routings. Return spring(s) not shown.