Cooper, Willis and Elaine Aroha Tongia then accompanied the teenagers back to a residential address where the firearm was produced again and cash was handed over, it is alleged.
The dispute stemmed from the sale of a cellphone to Willis.
Tongia, 32, was granted bail by police consent by a court registrar this morning and has been bailed to a Christchurch address.
Cooper is subject to strict bail conditions including not taking drugs and alcohol, a daily curfew of 8pm-6am, not associating with her co-offenders, victims or witnesses, and an order preventing her from entering South Dunedin.
"If she is found guilty she will go to prison,'' Judge Phillips warned.
The court heard the whereabouts of Willis remained unknown, and police were concerned that Cooper might collude with her son to help him avoid police.
The firearm had also not yet been located.
The women were arrested by armed police at a Maitland St property later on September 16.
The pair were to reappear in court on October 14.