Judge Jelas told the court the defendants were all in isolation for Covid-19-related reasons.
It had previously been revealed Hart had tested positive for Covid-19 after his death.
Police had earlier said they believed the fatal shooting of Hart, a father of two young children, was not a random incident.
His family have requested privacy to deal with the tragedy, police said.
Police were called just after 10am that Friday to New Haven Motel where Hart was found injured in the driveway.
Officers provided first aid but Hart died at the scene.
Armed officers also blocked a street in Green Bay, about 10 minutes' drive south of the crime scene.
About an hour was spent searching homes and garages in the suburban street after the incident.
