Hello All,
Well I am done and can declare success! Again I have to say thank you to many people on this forum but the most help was acomiskey and his post around OEM DVD Entertainment System Install Completed found here:
http://thenissanpath.com/viewtopic.php?t=1339
First let me define what I was hoping for. I wanted to keep everything as stock looking as possible, full entertainment for the kids, have kids DVD playing in the back while the wife and I could listen to music in the front. Well two out of three is not bad. I was hoping that when I connect the DVD to the factory HU it would play in the back only and I could listen to Satellite in the front (I have this setup in my other car with a Kenwood HU). The Pathfinder unit does not support that function. I know there are a few different way to get this done but decided just to connect it directly to the HU.
I spent a lot of time understanding what need to be connected and pins. FES and all that stuff. I was very excited when I started pulling apart the dash to tap into the M46 connector for the audio. Imagine my surprise when I got there and I did not have an M46 connector. Well that changed the game a little. The first thing I had to do was figure out how to connect to the M46 pins. To get a new factory harness was about $800 b/c the DVD does not seem to be a dealer option. I ended up buying a Metra OEM harness #71-7552 and then I grinded it down till I had 5 pin holes both top and bottom. Below are shot of the back of the radio, the diagrams from the service manual for the M46 connector and which pins you will need.
The wires in this picture are just temp, I was testing that I had the correct M46 connector until the 71-7552 arrived.
You need to jump pins 39&40 together so the HU think a factory DVD is connected.
I just soldered a set of RCA wired to the Metra connector. The next part only took 30 mins. I stalled the headrest DVD players. The DVD players I bought were off of ebay from lettucetrade. They were Pair 9" Headrest LCD Car Monitor 2 DVD Player USB BLACK. They matched the interior very well and seem like good quality. I am glad I went with the 9” monitor and not the 7”. To install them was very easy, just open the back of the seat (that made me nervous b/c it was a lot of pulling and prying). Slide in the new headrest and run the wire to the bottom of the middle console. I also wanted the driver to have full control of the player which meant a DVD player accessible from the front and a power switch just like acomiskey used. Then I mounted the Myron & Davis AD212 player in the arm rest section. There were a ton of wires but most of the connections were RCA but I also put connectors on each screen so the seats can be pulled out independently as well as the middle console. The only thing left was installing the power switch but that was simple almost everything had only two wires, positive switched and neg. Also note that that I used a PIE LD1 to make sure the input volume was about the same when you switch between radio, CD, and Rear AV (DVD). Here is the console all wired up:

This made it very easy to connect the RCA connections from the Head Unit to the PIE-LD-1

Here is the finished middle console

And here are the DVDs installed and playing a DVD from the middle DVD player

On a final note, the cool thing is that each headrest has their own DVD player (and yes you can link them together to play one DVD but that would be very hard for the driver to control.) as the kids get older they can watch their own DVDs and I don’t have to do a thing. The units can with a pair of headphones and even some games.
Hope this helps others.