Do the rear side marker lights work, there on the same fuse? Yes they work fine.
Are any of the bulbs that don't work dual filament such as combo brake/tail bulb. If so, does the brake light filament still work in the bulb? Yes the dual filament bulbs are dead, both filaments, brake light and tail light. The bulb itself is OK I checked that.
Is the bulb out icon on the dash light? Yes that is on.
Use a voltmeter to check for power at the sockets. There is power at the quick disconnect that goes on the wires at the bulb end.
Make sure the ground wires to the socket has continuity with the chassis. Where is the ground wire(s) Perhaps that is the problem. I did not see any wire hooked on directly to the chassis