I think it depends on how EI want to structure their medium haul routes post 2015. It has a unique mix of routes, BOS is highly seasonal and with weak-ish front cabin demand, but overall good volumes. JFK and ORD would be the year-round strong routes, with good demand in both cabins. MCO, again highly seasonal. I don't see the NEO or MAX being of much use in DUB, unless they want to use them to introduce some daytime eastbound departures from NYC.
I think the NEO & MAX should be able to serve BOS & JFK just fine, anything else would be a stretch and take a massive hit on cargo as well, so it would have limited uses out of DUB. So where would EI use 5 NEOs?
My thoughts would be:
DUB-YYZ/YUL
Daytime NYC-DUB, possible DUB-EWR, possibly DUB-IAD. -unlikely unless EI join STAR or STAR ATI
SNN-BOS - almost certain
SNN-JFK - almost certain
SNN-ORD - an outside possibility, if the range would work
ORK-NYC/BOS - probably more likely than SNN-ORD or a daytime EWR-DUB.
BFS-NYC/YYZ/BOS - again a possibility.
Frankly, 5 seems a bit on the low side, I could see 2x SNN (NYC, BOS, ORD) , 1x ORK (JFK, BOS), 1x BFS (BOS, YYZ), 1x DUB (EWR/daytime JFK).