Continental borders:
As continents are often defined physically, their borders are too. Where
a political entity overlaps a physical continental border, the country is
usually defined as belonging to the continent its people/culture are most
similar too. Hence Indonesia is an Asian country, because its people are in
the majority Asian, and the majority of the land is on the Asian side of
the boundary, and most contact throughout history was with Asia.
The Asian/Oceanian border is the Wallace line, a deep trench through the
archipelago (between Bali and Lombok I blieeve, and between Sulawesi and
Halmahera (sp?)). This was described by Alfred Wallace, a precursor to
Darwin, who noticed a dramatic change in speciation across this boundary
because the trench was waterfilled, even thousands of years ago when the
rest of Indonesia was connected to Asia by land. Thus the spread of people
and animals and plants across it was difficult, and resulted in their
isolation from the Asian mainland, and thus a different evolutionary pattern.

West Papua, if independent, would be Oceanian, not Asian. It is totally
different culturally from the rest of Indonesia, a fact the Dutch
recognised, but weaseled out from in the 1960s.

GERMAN colonies:
Western Samoa was German before being captured by NZ in 1914.
Nauru was too, and became an Australian/NZ/UK codominion, and was
ruthlessly vandalised for its phosphate.
Qingdao (Tsingtao), like the Pac Is Trust Territory was German, until taken
by the Japanese in WW1. The Japs lost the Pac Islands to the US in 1945,
but Qingdao was returned to China, as it too was an ally in WW1. With the
return of Qingdao, Britain was able to relinquish Weihaiwei on the north
side of the Shangdong peninsula, in the early 1930s as the only reason the
Brits obtained that base was because Germany has grabbed Qingdao (and
Russia, then Japan >1905, Port Arthur/Luta/Dairen).
Interestingly, Chinese troops from Weihaiwei, under British officers,
fought with the relief column against the Boxer Rebellion/Siege of Peking.
The French used Tonkinese troops under French officers.

Germany also had Namibia, Cameroon, Tanganyika-Ruanada-Urundi and Togo.
Zanzibar had been swapped with Britain for Helgoland in 1900 or so.
Tanganyika became Tanzania (with the addition of Zanzibar and Pemba),
German SW Afrika became SW Africa under S.African mandate, then Namibia in
1990. Cameroons became French Cameroon, though a slice on the west voted to
join Nigeria. Togo was also split, part joining British Ghana and part
becoming French Togo. Ruanda-Urundi became Belgian Rwanda & Burundi.

BW