Ok, you should be able to measure 11-14 volts on pins 3 and 4 of the ABS connector. If it’s not there, check fuse 11. Ignition should be on when taking the measurement, but disconnect the connector with the ignition off first.
If the voltage is there, I suspect you are correct and your ABS module is probably bad. You may need a MB Star machine to reset the system after installing the new pump and bleed the air out.
I don’t believe so. There is a single large electrical connector that incorporates all of the signals to the ABS module and nothing appears to me to be replaceable, but my memory stinks so you may have a different impression.
The module is not difficult to replace, save for lots of spilled brake fluid, but be very careful not to cross-thread the brake line fittings.
After you replace it, you will need to do a careful job bleeding all 4 brakes. Prior to my acquisition of a MB Star machine, I had to take mine to the dealer to recognize the new pump and bleed the brakes. I was able to bleed most of the air from the system, but a slightly soft pedal lead me to believe there was still some air trapped in the pump itself. The dealer was able to bleed the brakes properly to restore pedal feel, bit like all trips to the dealer, it’s pricy.