They dont actually call themselves the Olivians. That Tribe name is Indigenous Australian. It comes in the form Gajalivia and you certainly see the Olivia name proving the far migration of peoples. The tribe in the Mediterranean refered to themselves as 'Athal'. They seem to have produced the vowels you take for granted exanding ul into al, el, il, ol.
They have a nice linguistic database that defines them:
To erect, post, beam, to excavate, gate, human settlement; fortified high place.
Needle, skin bag, hide, carving, grind/mill, drip (tallow), dish, bundle, wool.
Wild woods, prominent hill, rock/cliff.
Willow, molly, hazel, grass reed, olive, apple (tree fruit).
Crooked, limb, to fall, honey.
To take, to decieve, To fight, yell, to strike, to destroy, obligation, to spread flat, To sell, to count, to travel.
Speak with god, lightning, sun.
Who are they? They have goats and milled grain and olives and other tree fruits. They fight amongst themselves and with others whom they also trade. They live in timber frame dwellings and have a high fortified location. They work with sewn leather and wool.
They are surrounded by wild woods. One location of long settlement on a prominent hill/rocky cliff/high fortified position comes to mind: Troy with its many thousands of years of occupation. Settlement layer on settlement layer. Descended from neanderthals.
They worship a god associated with lightning and possibly the sun. Are these people related to the Gajalivians? Olives seem the indicator. They also have made contact with modern humans in a way similar to the Neanderthals of Australia. Where Ngulwun is the early indigenous Australian form of Alvin, Angelos means messenger. As names go Angelo would be related to Alvin.