Short answers, pulled from the story.
The Territory of Papua formally constituted on the 1st of September 1906 when the Papua Act 1905 took effect. King Edward VII issued letters patent placing British New Guinea under Australian authority on the 18th of March 1902, but a four-year interregnum period followed before formal constitution.
Hubert Murray was subsequently appointed lieutenant-governor until 1940 following the suicide of acting administrator Christopher Stansfield Robinson. A royal commission inquiry into allegations of massacre during Robinson's punitive expedition to Goaribari Island in March 1904 led directly to his death and subsequent administrative changes.
Australia invaded the northern part of New Guinea which remained under German commercial control from 1884 on the 11th of September 1914. Two thousand volunteers formed the Australian Naval and Military Expeditionary Force to capture the entire German colony known as Kaiser-Wilhelmsland by the outbreak of war.
The Whitlam government oversaw independence for Papua New Guinea on the 15th of September 1975 while Andrew Peacock served as Minister for External Territories when self-government began in 1972. The Papua and New Guinea Act 1949 had previously united two territories administratively despite maintaining distinct legal statuses.
Japanese marines attacked a strategic Royal Australian Air Force base at Milne Bay near the eastern tip of Papua in early September 1942. They were beaten back by the Australian Army during August and September fighting, marking the first outright defeat of Japanese land forces in the Pacific theater.