How do you come top the conclusion that it is one of the rear sensors?
It's easy to change,
Remove wheel
Remove brake caliper
Remove brake disc
Undo screw holding sensor in hub and remove sensor
Unplug wiring and refit new sensor.
I also have all the ABS lights showing but am at a loss as to how to identify the cause although I have removed and cleaned up all my sensors, replaced discs and pads.