All the above assumes that 'hilo' or whatever it's origins or derivatives are, is a word.
I'd suggest that it is actually a meaningless vocable.
Think about the vowel sounds that are easy to produce in a loud shout.
Nobody shouts "EEEE stop thief!" or "OOOO there!"
One of the best set of frequency formants for producing a loud, well projected sound is the one that lies between those for "o" and either "i" or "a".
So we shout "OI! PACK IT IN!" and football crowds sing "WAYO". The banana boat song gives us "DAYO", and very close to all of these comes
"HELLO" and "HILO".
I think that you should look for 'hilo' not in literature, but in the physiology of human speech. Everything after this is post-hoc rationalisation.
Cheers
Dave