If convicted of at least two of the murder counts, the 30-year-old Balfour, on parole at the time of the killings after serving nearly seven years for attempted murder and vehicular hijacking, would face a mandatory life sentence. Hudson, the 2004 “American Idol” finalist and 2007 Oscar winner for her role in “Dreamgirls,” is expected to attend each day of testimony. It could last up to four weeks. She was joined on Monday by her fiance, David Otunga, and other family members. Professionally, Hudson has had a busy month so far. She recently performed on “American Idol” and also sang at The Revlon Concert for the Rainforest Fund at Carnegie Hall, in New York. She appears on the soundtrack to the new film, “Think Like a Man.”