They died at the scene.
Neither Morehu nor Davey was in the crash vehicle.
In court today, Reihana and Davey were remanded to reappear at post-committal conferences in Manukau District Court next month.
Despite opposition by police, curfew conditions were also lifted for Davey.
His counsel, Paul Mabey QC, argued a trial for Davey could be as far as a year away.
Outside court, the family's social worker and spokesman James Papalii said Haki was travelling three cars back from the vehicle allegedly driven by Reihana and his family was "dumbfounded'' at the charges against him.
"They can't believe he's up for two counts of manslaughter.''
The wider whanau remained "traumatised'' over the tragedy, he said.
"This was a five-minute ride to the cemetery to visit their grandmother and, okay, they were speeding and it got out of hand, but they never thought anything like this is going to happen.''