Well, its been a bit since I had some time for the project. Lately I have been modifying the cart reader, soldering that, and now I am adding all my wires to a good Pi Zero.
I did test the image I had against another Pi I have on my TV. I couldn't tell that I was missing anything. All of the games I tested were centered and none of the items were cut off the screen. When I SSH into the Pi none of the scripts run off screen either. So far so good!
Cartridge reader modifications:
Got these from Ebay, and I am not sure, however think it is the GBA reader from a DS, the 'Cart 2' slot as he called it. Had to trim a fair bit off the sides to sneak it in there with the way I have to route the HDMI adapter.
Soldered up
Thanks!