I am not sure I accept your contention that suicide causes public shame and humiliation. Ernest Hemingway, author; John Robarts, former Premier of Ontario; and Margot Kidder, actress; are just examples of suicide victims whose legacies I believe are intact. With the availability of Medically Assisted Suicide legal in Canada now, I do not think the stigma still exists. There are schools, and libraries still named after Robarts.
If one of the goals of the perpetrator(s), besides killing them, was to shame and discredit the Shermans, there much more effective ways to do it.
I may be way off, but I feel the staging was not about tricking the TPS into believing that is was a M/S and the subsequent shame, but rather something much more significant to the perpetrator's relationship with the victims.