Actually, I always saw any EK plan to fly to DXB as a means to stop EK coming to Dublin. If EK were to come into DUB, it would be far more aggressive than GF (given the size of its network - and its shopping list) in growing the market.
EI doesn't have the marketing prowess, the name of the service product to compete with EK, so - if it wants to keep them out - fly to DXB - and not necessarily to feed into EK's network there. Whether EK would be put off by EI or GF I don't know, but if I were DM, I'd want to keep EK out of DUB for as long as possible.
As for SIN, can it be done with a 332? Perhaps out, but what about back, against headwinds and low FLs over India? I doubt it. The 777 can't do it economically out of DUB. Personally, I think the most likely Asian route for EI is HKG - far more central geographically and feeding into CX hub.