Published Wednesday, 21 October 2009
A need to clarify a number of "evidential issues" meant that not all those individuals could appear as scheduled, the coroner said.
Among them was the lead police inspector investigating the fire and relatives from both families.
"It's important there's no undue delay in completing the inquest now that it's started," the coroner added.
Arthur McElhill, his partner Lorraine McGovern and their five children all died in the fire in November 2007.
On Wednesday the inquest heard McElhill was treated for depression two months before the fatal blaze.
The 36-year-old convicted sex offender, who had a history of suicide attempts, has been suspected of setting fire to the property using petrol and white spirits.
Dr Michelle Mellotte told the second day of the inquest into the seven deaths that she had prescribed Mr McElhill with anti-depressants nine weeks before the incident.
The GP also confirmed to coroner Suzanne Anderson that he had tried to take his life before - notably in 1988 when he drove a car into a wall.
"He was really down and depressed," the doctor said of his mental condition in September 2007.
But, the medic said she did not believe that he was suicidal at that stage.
Relatives from both the extended McElhill and McGovern families listened to the doctor's evidence from opposite sides of the court room.
Later a number appeared visibly distressed as firefighters who tried in vain the save the family recounted the moments they discovered the seven bodied in the upstairs rooms.
Fire service area commander Eoin Doyle revealed that at the height of the blaze the temperature inside the house had reached at least 700C - hot enough to melt glass light bulbs.
Crew commander David Canning said nothing in his career could have prepared him for the graphic scenes that greeted him.
"I haven't seen anything like it in my 18 years as a firefighter," he noted in a written statement read to the court.
The coroner later explained to the court the McElhill family believed another person could have entered the house and lit the fire.
She also noted that one eyewitness - Lee Anne Duffy - was "98% sure" she had seen Mr McElhill outside the house four minutes before the fire started.
Legal representatives from the McElhill family made an application to the court.
Details of the legal move were not made public.