@Shakespeare:
If after war has started and no one has claimed Borneo Sumatra, may the Brits land airplanes there?
Yes, but it will not give them control of it. Taking control requires land units.
@Shakespeare:
who gets the IPC’s of Borneo Sumatra after war starts with UK?
Whomever has claimed/invaded it.
@Shakespeare:
If ANZAC takess Borneo Sumatra before the UK gets there who gets the IPC’s? UK or Anzac?
ANZAC.
@Shakespeare:
Who gets Borneo’s Sumatra’s {PC’s after war starts but no one is there?
If no one has claimed it, no one gets the income.
Questions like these can be answered by applying a simple principle. If the situation isn’t specifically dealt with in the rules, treat the Dutch and French territories in exactly the same way as Allied territories whose capital is held by the enemy.