I got an authoritative answer from EMC guys:

1) EMC can use limit switches when homing.

2) When not homing (ie when it knows its position and limits), EMC will never
permit any command to overrun limit switches.

3) When not homing, EMC will treat any limit switch as an alarm signal
and will stop.

4) EMC can handle both NO or NC limit switches. Mine are NC and no
problem for EMC.

I will wire my stuff to use limit switch signals through software and
will double test the operation of same.

i