Since the ERn has four dry input contacts on the left I/O, can I land an emergency system on one of those contacts to trigger a preset or other in action in Paradigm when the emergency contact has been triggered?
No. The ERn is not rated for any type of UL life-safety. Emergency contacts should go directly to the power control rack which directly provides the power to the emergency circuits. All ETC UL924 rated power controls have a built-in panic header for this purpose, and can be used in conjunction with an EBDK (Emergency Bypass Detection Kit), DEBC (DMX Emergency Bypass Controller), ELTS2 (Emergency Lighting Transfer System 2), or SC1008 (Branch Circuit ELTS) to satisfy any UL924/UL1008 requirements.