Since EI haven't placed and order for any aircraft although one will happen soon as they need to replace some short haul fleet, it will be at least 6-10 years before the 321NEO comes to EI if ordered and the aviation industry will have changed a lot so I would take this with a pinch of salt as I don't see it happening TBH SNN year round yes Cork maybe but Belfast can't see it regardless of what airport although BFS only option. I'm sure BFS management would welcome them back with open arms if they were to offer a JFK service!! With these A350's coming (think they should sell there order to another carrier or replace order there will be major capacity to fill ex Dublin and BFS and DUB services will not both be viable IMO.
A321NEO not starting until 2015 so it will be close to 2020 before EI get them if ordered as they will be back of a long list of carriers who have ordered NEO aircraft.