There's a rumour that the Chinese jets landed at Perth instead of RAAF Pearce, despite some fairly serious protests by the ATC. This may be a very interesting cooperative SAR effort.
As a lifelong Orion (and Neptune) fan, I have a hard time believing what I'm about to say: I think this is probably one area where the Poseidon may have an advantage. It will have shorter transit times to the area of operations, it is able to be refuelled in-flight, and it's capable of carrying a relief crew. It's not the world's worst choice for this particular case. It might be butt-ugly, graceless and devoid of character, unsuited to low-level work just above the waves, but it does have a few upsides.
What good the Chinese are going to do remains to be seen. I understand they lost a Y-8 in the sort of weather conditions to be expected out over the search area some time ago. I am cautiously optimistic that everyone will work from the same sheet of music.