First thanks to all who posted the how to guides on controller configs. I have the 2-USB retrolink controllers and have used retroarch to configure player 1. When I edit USBGAMEPAD.CFG for the second controller everything breaks.
I don’t think the player two line is needed. I am using a USB SNES controller and a PS3 controller and I didn’t need to put any player two lines in. Altho RetroPie thinks my PS3 controller is a Xbox controller due to some kinda driver mishap? But leave the .cfg files as default and should be fine.