Back to the panel..
With my multimeter, with the black probe on the ground bus, and the red probe on the terminal screw of the main circuit breaker, I read 126v. Same deal with the red probe on the neutral bus and black on the ground bus.
If you have 126 volts on the neutral bus you have a serious problem that should be corrected before proceeding with the 12 volt problems. See the graphic above posted by RoyB. There should be no breakers on the neutral so that is not the problem. My guess is that you have a floating (disconnected) neutral. This would explain why none of the outlets work.