I can speak to the second camera issue. Take a look at my Misc album, the extra camera looks over the top of my JK toad. I made the mount for the camera and attached it with one of the window screws, the blind still functions as normal. The factory camera looks down to the point that the blue ox bumper pins are just at the bottom of the mirror screen. I mounted the camera's transmitter at the foot of the bed, and the screen is mounted with the XM receiver on a removable inset in the dash. I power the camera from the rear tv 12v source.
I can see traffic behind toad which was the objective.
Hoglou the DH (01.01.21 done and retired)
BK the DW (retired and happy)
WestGA KM4HQQ 146.640mhz
L'IL Foot" 2014 Sunseeker 2300
"Harry" the JK toad in the mirror
Check out the "mods" in the albums