Just on the layover point, if you're going between Australia and Europe you more or less don't have a choice but to stop somewhere. Other than a Perth-London flight, the closest to a non-stop flight from the east coast (where most people live) is Sydney-Istanbul.
Those flights are brutal (usually around 24 hours with the stopover), so it has become increasingly common to break it up with a few nights somewhere. I know I now do this on the way back to Europe. So, this is certainly a market they would be wise to consider for the resort, particularly as Etihad is well-established flying between Australia and Europe with a stop in Abu Dhabi. It would be win-win for Etihad and Miral to work out deals that both make Etihad a more attractive choice for those flights and Yas Island an attractive break for a few nights on the way there or back.