I would be surprised if we took ANY A350-1000. It's not quite enough for EK against the capability of the 777-8 and -9.
However I'm certain we'll see the 350-900 on lower capacity routes that currently demand a 330 / 340 / 772.
Maybe the 20 -1000s already ordered will be converted to top up the 380 or 359 orders.
I'm going for 175 77X, a mix of 8 and 9s.