GAF built Lincolns but flew US built Liberators during the war, why not GAF or DAP as it was then, building Lancasters during the war, as Canada did, then follow the with Lincolns and then Shackletons?
There could even be a bomber version of the Shackleton that GAF builds from the late 40s before building the MPA Shackleton instead of the Lincoln Mk31. Both could be built in improved versions through the 50s for the bomber and into the 60s for the MPA incorporating advanced compound engines then turboprops as well as improved weapons, systems, sensors etc. The bomber would eventually be replaced early 60s with V Bombers while the MPA would be replaced with a jet MPA in the 70s or even the 80s. There could be a multitude of special variants, AEW, ESM, even attack versions developed for COIN in the maritime and littoral environment during the Malayan Emergency and Indonesian Confrontation but then successfully employed over Vietnam.
The Canberra would still have entered service but as a replacement for the Mosquito, Beaufighter and Beaufort while the Lincoln, Shackleton and Shackleton like bomber would have been replacements for the wartime heavies and Sunderlands, i.e. a larger more diverse RAAF.