RPG,
Well, we'll see! The A350 is no more than a Cad-Cam program at the moment, if Airbus don't get it out on time, I suspect EK will tell them to stick it and get more 777s, possibly 787s as well.
The A330 rosters are terrible at the moment. the 777 is taking over all the ULR flights, so, yes, they are doing the brunt of the night turn-arounds.
I don't know what routes in particular will be A350, but I think it's more medium-haul than ULR.