Kenneth Branagh made his presence felt, so it certainly did not feel like a minor role to me.
The aborginal tracker was beautifully played by David Gulpilil, he was definitely not a villain - see the review by Stephen Haines.
He was caught between his white employees, who had his daughter at the mission, and who he was.
He wanted to return to his home with his daughter, watch his face when Mr Neville refuses.
He was having to make the best of a very unjust world.
You see his growing admiration for Molly as she outwits him.
And near the end of the film, you see him smile, he knows they are close and it was his best chance to catch them, but he deliberately lets them go.
He is with a white man/tracker at this point in the film, & it brings home to the viewer the conflicts he is facing.
So beautifully & subtly played with no words needed.