GOT IT WORKING!!!
It required to choose a probe type, so I uncommented
893 #define NOZZLE_AS_PROBE
and
1391 #define Z_SAFE_HOMING
and the Z parameter sign needed to be negative in:
991 #define NOZZLE_TO_PROBE_OFFSET { 0, 0, -3.09 }
One problem I thought was the firmware but was a Repetier Host problem: It won’t allow you to move Z to a negative value after Z homing using the arrow interface. You need to use G codes.
I wish there were a setting in Repetier Host that made it more CNC-friendly, and stopped using the word ‘print’ and ‘printer’ after you selected it!