There are now rumours that the whole incident was backed by Malaysian politicians opposed to the government party, hoping to use the crisis to attack the Prime Minister. Whether these are true or not, I have no idea. But the invasion demanded money and resources that its nominal leader, the Sultan of Sulu, probably lacked. Somebody is behind it.
In The White Rajah I simplified the protracted negotiations that gave Brooke control of Sarawak. Court politics in the mid-19th century was a Byzantine maze of family loyalties, political coalitions, treachery and death. It really does seem that not a lot has changed.