Here’s what I think QR is going to do in terms of product commonality.

this new order coming up is for over 200 jets and is said to be for the A350 and 777X

so if we’re going 50:50 as QR have always done you’re looking at 100 A350s and maybe about 50-75 777-9s

The 100 A350s will be mainly made up of the 900 variant.

the A350 will replace older A350-900s and 787-8s which will be retired out of the fleet.

all will have qsuite next gen the 777-9 fleet will go up to about 130-140 aircraft used to replace the 77W and a380 and for a bit of network growth

the 787-9 will be relegated to regional or under 4 hours flying.

A350-900 and 777-9 will be the most popular jets in QRs fleet.

this is just my take based on the information we have