The two men were convicted of his murder, while Jamie Ahsin, who was driving the car, was convicted of manslaughter.
Rameka was charged with being party to the manslaughter.
The Crown said while she took no part in the attack, she shared a common intention with the rest of the group to assault Mongrel Mob members.
Mr Kumeroa was not connected to the Mongrel Mob, but the red colour of his hoodie is associated with the gang.
Rameka's group is associated with Black Power, an enemy gang.
The group had a run in with a Mongrel Mob member and associate earlier in the day, and then initiated two more conflicts with people they suspected of being connected to the Mongrel Mob, the Crown say.
The defence argued the incidents were not-gang related, and there was no shared intention to assault anyone, as nobody was assaulted during the earlier conflicts.
Defence lawyer Elizabeth Hall said McCallum was acting alone when he used the axe on Mr Kumeroa, and that the other three had been trying to get him back in the car before he did it.
Witnesses spoke of hearing at least one female voice yelling "get back in the car", though who was yelling it and when during the assault they yelled it was not certain.
The trial, before a jury of six men and five women, started in the High Court at Whanganui on Monday last week, before Justice Rebecca Ellis.
Lance Rowe was the prosecutor, while Ms Hall and Christopher Stevenson represented Rameka.