Two other people received minor injuries during the incident.
Victoria Police confirmed on Wednesday afternoon a 43-year-old man and a 45-year-old woman, both from Werribee South, were continuing to assist them with inquiries.
A second female had been released without charge.
Michael Gauci, 43, has been charged with attempted murder and appeared in the Melbourne Magistrates’ Court on Thursday after spending the night in police custody.
He was flanked by two court security officers as he was led into the courtroom, pausing briefly to look at six loved ones sitting at the rear of the court.
His lawyer Anthony Malkoun told presiding magistrate Donna Bakos this was his client’s first time in custody and requested he see a doctor for “unspecified health issues”.
Police will allege a woman suffered life-threatening burns about 2am on December 28 after Gauci “intentionally” set her on fire.
She was allegedly in the front yard of a home in Rivercoast Rd, Werribee South when the alleged incident occurred after a “dispute”, police say.
The Werribee South man has been charged with attempted murder, conduct endangering life, intentionally causing serious injury and recklessly causing serious injury.
Homicide detectives initially attended the scene after the first callout, but the arson and explosives squad later took over the investigation.
Gauci and two women were brought in for questioning after the alleged incident.
Later the same day, police said one of the women was released without charge, while a 45-year-old woman from Werribee South was released pending further inquiries.
A teenager was also taken to Sunshine Hospital in a stable condition with upper and lower body injuries and a man in his 40s was taken to The Alfred in a stable condition.
Gauci was remanded into custody and will next appear in court in March.