The A330s are intended as an interim solution; I doubt very much if the stated cost of EUR330m is correct. That would be fine if they needed the aircraft indefinitely, but these will be leases for about 7 years, until the 350s become available.
My guess is that EI is doing a pretty long term deal with Airbus, with will cover its short and long haul fleet and this deal is only the first stage of it. This will cover supplemental capacity, but they will need to replace the earlier A330s, as I don't think these can be fitted with PTVs and a modern IFE without weight penalties which would rule them out on the ORD route.
The A340 isn't much use to EI; it's a pretty poor performer (the -300 anyway) and Dublin's runway length would limit its performance considerably. You certainly couldn't get it to fly any further than Chicago and east coast routes (incl. FL). They might, if nothing else were available, lease some for a short time, but in the long term, it's long haul twins like the A330-200/300X and A350.
As to PTVs, certainly these have to be fitted. Only one of the 332s is fitted now - 'DAA and with the new DXB route starting in late March, they need to have the other two retrofitted. Starting a new route like this (where there is so much competition from the likes of EK) would be a very bad move; this is (literally) a new departure for EI and it needs to get itself known as a respectable brand; starting with a second rate Y class would be a false economy. DM knows only too well what an aggressive competitor EK can be and there are lots of alternatives from DUB; VS is starting to DXB this Summer as well.
(Don't forget that when flying to the US, it's a pain to have to travel via LHR, but when flying east, it's pretty much the same direction, so EI can't count on people settling for a second rate product if they can get much better via LHR, CDG, AMS or wherever.)
In response to Neidin's comment (which I didn't see as I was posting this at the time), I totally agree, but I've always wondered why there is such a muted protest by EI - or even IALPA - to the whole runway issue. It's not just EI's issue; it really makes DUB a very undesirable destination for long haul carriers. Only recently, Comrade Minister was in Singapore and BKK talking to SQ and TG; how do you sell an airport like DUB to airlines that have aircraft than can fly n/s - but can't because of rwy limitations?
