For Earth GND it is normal practice to set up a star point ground bus of some kind on the panel component mounting frame, for one earth central termination point.
Also see the Siemens publication I have posted a few times before, for equi-potential bonding of the M/C.
For E-stop, it is required that all power to motorized devices be removed whenever E-stop is activated.
You can find/search a copy of NFPA79 (Electrical Standard for Industrial Machinery) out there.