I think the loss of the ANZ deal, which must have been a near certainty for Airbus, given that the 332 was such an ideal aircraft and it already had 320s, was a wake up call to Airbus. As you say, Boeing is in fight mode and it has already targeted 200 7E7 sales this year, which I think is achievable.
In EI, it sees a very ambitious airline with high growth plans and with that kind of potential, you can be sure Boeing will go in all guns blazing to get this. Although the 7E7 is mentioned as the competitor, I don't think this precludes the 777 coming into the fleet, particularly as a 333 replacement; I think there are a few 333s coming off lease fairly soon and these could be replaced by 777s. Also, Boeing has an incentive to help Aer Lingus to meet its growth requirements, particularly over the next year or so. With the 332 doing so well and with delivery slots taken up and very few on the market, can Airbus do this? I doubt it. I'm not sure how many 777s are available now, but I think that if Boeing wants to get an EI deal, it will need to be seen as a strong supporter and facilitator of EI's growth. As I said, with Open Skies on the horizon, EI's fleet needs will be increasing and it has said it wants to add three new US cities as soon as it can.
Basically, it'll come down to who wants this deal more; Boeing can get it, if it wants it enough.