I wired my UB1 similarly as shown in the diagram attached. When the eStop is pressed, the relay is de-energized and cuts 24v power to the Nema drivers and also cuts the x103 circuit which triggers the software estop.
I do not know how to use the same estop to turn off the vfd. I only mentioned FA & FB from an older post where someone used it for estop but did not specified how.