There is a plethora of scenarios which can be imagined to support the acquisition of F35Bs for the RAN but any acquisition of capability must be constrained by the governments stated strategic policy detailed in the DWP 2016 and clearly laid down in the Executive Summary
http://www.defence.gov.au/WhitePaper/Docs/2016-Defence-White-Paper.pdf
In short Australia has three laid down Defence Interests each coupled with a Defence Objective.
The first two are basic; 1provide a secure and resilient Oz, deter, deny, defeat any attempts etc, 2 secure our nearer region, Maritime SE Asia and the S Pacific, secure the governments of PNG, Timor-L Este and the Pacific Island countries, and,
3 and this is the most relevant to any F35B conversation, provide meaningful contributions to global responses to address threats to the rules based order which threaten Australia and work closely with the US and others.
The nearest scenario under which we may think about an organic fast jet capability is the last but I can’t see any reason how a “meaningful” contribution could be provided if we are working closely with the US or others.
If our government changes these strategic objectives to something quite different which may include unilateral power projection then maybe a case for the capability could be made but not now.