A lot of vehicles from that timeframe had the DVD load up into the sat/nav head unit. I test drove a lot of them and honestly they are all running together in my head.
This is a basic question, sorry to have to ask it but do you have any other place to put a DVD in anywhere? I can't recall if there was a set of rca / aux input jacks in the back of this vehicle either where you could bypass it all.
One way or another there is either a dvd player in the vehicle passenger area, or it's been removed. Either way, the wires for the screen are very likely behind the current JVC head unit and could be plugged into a new dvd enabled system or pulled out and moved so they could be plugged into a portable system.
In-car entertainment systems have changed a lot since then, honestly I've not touched a DVD in 2 years as now each kid has a tablet device and we just turn on tethering when we go somewhere and have a data limit set so that we don't go over our data plan.