Aer Lingus have by far the best profit margin in the group, just shy of 30% vs BA at #2 who are in the mid teens IIRC, so giving new A330s to anyone other than EI would be madness, hence why they got 2 this year and two more next year.
EI did okay operating MAD-IAD for UA a couple of years back, crews were based in IAD, and loved it apparently.
On paper EI look great but have yet to be challenged by low cost on T/A.
WW im sure specifically said VY would concentrate on short haul only.
They say a lot of things but cannot stick to them if conditions change which they have.
I agree it will most likely be operated and branded as Vueling but they are been a little optimistic for getting a S17 start unless it's advanced internally which I suspect it's not.