In terms of coffee, Oceania is a grouping of outliers. For example, Australia barely produces coffee, partly for economic reasons, but also because they very limited locales that can produce arabica coffee. 

Papua New Guinea does have more in common with the islands of Indonesia in terms of climate. But there is less in common in terms of coffee flavor characteristics. 

Hawaii is (only by some definitions) part of Oceania. It is hard to place it in this geographic area, but not so much in terms of island climates.  We put Saint Helena in here because we just don’t know what else to do with it!