Perhaps the archipelago would have a Chinese name if they remain politically disunited? If alt-Portugal and alt-Brunei are not able to conquer the whole archipelago, they may not feel the need to give it a unified name as this might imply they 'failed' in their conquests, but Chinese merchants would have no such point of pride and would want a common name for the islands for their maps and directions.
Possible names: Pirate Islands (if Chinese pirates take shelter there), Land of Wood and Honey (two commodities Chinese traders sought), Gold Mountain (if urban myths about Philippino wealth still develop ITTL).