RE surely have a service level agreement with EI, so potential disruption cant be good, and could end up costing RE a fortune! There are plenty of regional carriers (Flybe comes to mind!) that would jump at the opportunity to operate the Aer Lingus Regional services for Aer Lingus!
In better news, DUB-NCL is available for booking on aerlingus.com; seems to be daily and varies from mid morning to evening departure, which offers good connections to/from the USA