If cost is a definite issue I would consider the following routing…. Apologies that I don’t have time to check fares, maybe Tim can help….
Firstly keep an eye on FR/EI deals from EDI >DUB>EDI and book separately, you’ve now avoided APD,,,,,,,,
EI from Dublin to LAX or a choice of DL/UA or US to their hubs…..I noticed that you could probably return from Orange County via ORD….
The main benefit I can see is that you’re pre-clearing US customs in Dublin…I would imagine that in these sequestration times , the Christmas period is going to be particularly painful….more travellers travelling and more officers on holiday !!