One of the problems with kick-starting a Pacific Island civilization is the lack of useful metal deposits. Some of the larger islands have copper and gold, but none have tin for bronzeworking and, as far as I know, none have easily accessible iron (Fiji and PNG have iron sand, but techniques for smelting iron out of sand weren't developed until well into modern times).
New Caledonia is something of an exception. It also doesn't have significant iron reserves, but it does have huge deposits of nickel ore, some of which is at 10 to 15 percent purity.
Now, I know jack about nickel smelting. However, nickel has a melting point of 1455 degrees Celsius while the melting point of iron is 1538 degrees, so a furnace that would melt iron would presumably melt nickel. Nickel is also both malleable and ductile, and can be worked.
Is there any chance, then, that the Kanaks could get the idea of metallurgy through working copper (which also exists on New Caledonia) and then progress to a "Nickel Age?" We know that it's possible to go directly from the Copper Age to the Iron Age, because the West Africans did so; could the same be done with nickel?
I'm probably missing something obvious here, so I'd appreciate advice from the metallurgists and geologists on the forum. There's presumably a reason nickel in its pure form wasn't isolated until the 18th century, although that may have had to do with the fact that deposits like those in New Caledonia are rare and were unknown at the time. But the idea of a classical Nickel Age empire in Melanesia is one that won't let go - could it conceivably happen?