I think a Chinese buyer is unlikely - the threshold for FIRB...

I think a Chinese buyer is unlikely - the threshold for FIRB review of foreign purchases is set at $0 at the moment. Under normal conditions it is $275 million for a sensitive business* with a FTA partner. Or 1.192 billion for a non-sensitive business. And $0 for all government owned entities.

*Sensitive businesses include media; telecommunications; transport; defence and military related industries and activities; encryption and securities technologies and communications systems; and the extraction of uranium or plutonium; or the operation of nuclear facilities.

I think the takeover process for 4DS will take some time once it is announced - there is going to be so much regulatory oversight. So, if this kicks off in March, don't expect a conclusion until September (6 month process with FIRB now)

Monetary thresholds | Foreign Investment Review Board (firb.gov.au)