Melissa Merritt, 33, and Christopher Fattore, 36, who live common law, each faces two counts of first-degree murder in Ontario.
"The request was what's commonly called a six-day remand," said Crown prosecutor Ron Lacey. "That allows the arresting agency, in this case Peel Regional Police, time to come down, take the individuals back to where the crimes are alleged to have been committed and then the individuals will face those charges there," .
The couple was arrested on Tuesday in the community of Italy Cross, near Bridgewater.
Merritt and Fattore are accused of killing Merritt's former husband, Caleb Harrison, 41, last August and his mother Bridget three years ago.
Police said both mother and son died of asphyxiation.
Barbara Eisener, 77, lives next door to the Italy Cross home and said her son rented to the couple.
She said she was shocked by the accusations.
Eisener said the eldest child living in the home would sometimes shovel snow off her steps.
Police believe Merritt and Fattore had been living in Nova Scotia for about four months prior to their arrest.