The trial heard Park, a window cleaner, plotted with convicted killer Platt, to murder Mr Ferns, who worked as a tiler.
Colquhoun acted as the getaway driver in a Motability car, which belonged to the mother of his then-partner.
Meanwhile, McCulloch was said to have been helping track Mr Ferns’ movements before the killing.
Mr Ferns’ partner, Angela McCann, told the trial how she could “see the life draining” from him after the attack.
He had just dropped Ms McCann outside her home following her shift at a convenience store when a man approached his vehicle.
Ms McCann had gone back inside to get her sister, who was babysitting her children, with Mr Ferns due to drive her home.
She said she spotted a man at her partner’s window but told the court she was not concerned as “Tony knew everybody” and believed it was likely a friend.
She heard the car suddenly screech and the vehicle head towards the nearby home Mr Ferns shared with his mother Phyliss, where it stopped.