United MileagePlus (Consolidated) - Different Fare Classes in same booking

Is it possible to fly

YVR->DUB on cheapest Available fare then
DUB -> EWR on Y (for upgrade) connecting to EWR -> YVR on cheapest available fare?

Also, if I use miles for an upgrade is it 15,000 miles per transatlantic flight or for the transatlantic flight + connecting flight?

Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9930; en-US) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.163 Mobile Safari/534.11+)

Can it be done? Yes. But it will price as three separate fares and might be more than you are hoping. You will have to have an agent book it for you; it cannot be done online.

As for the upgrade, it might price all the way through even with the split fare component but it also might not.