Let's look for a second at what a E-stop or Stop switch is in a circuit. All the contact does is opens the energising circuit of the Main Contactor. IE: It drops out the coil, which releases the hold-in contact and de-energises the circuit. Any Remote Stop will be in Series with the original and as long as things like Voltage Drop are taken into account, you should be OK. The Neutral really doesn't come into it.
