G'day all...
Just passing by and thought I'd add my two-bobs' worth:
Have you considered that the word 'pangulu/penghulu' does not refer to the title of chieftain/leader at all... but is associated to the word 'hulu'... which means the head/ukiran?.. In some regions... the two words pangulu/hulu are interchangeable and refer to the handle/grip (I believe such is also the case wrt the Bugis).
Cheers.