one thing I have wondered ... the last person who saw Lori besides her husband, was Mark's sister, and she said that was late Sunday evening.
It occurs to me that maybe Lori was hurt/gone by then, and Mark got his sister to lie about having seen her. If so, Lori may have been hurt even earlier?
Just before that, she was seen alive by many people at the Bounty housewarming party.
Let me know if you come across a source about Mark's sister (which one?) seeing Lorie at a time after this.
The convenience store was right near the Hacking apartment, so if one of Hacking's sisters saw Lori after that, it would probably have been at their apartment.
I've read nothing about Mark's siblings that would lead me to believe any one of them would be a willing accessory to murder, before or after the fact.