Megan did not appear to know that lemon and sea salt was a cleaner but in season 1 episode 2 there was a scene in which it was mentioned as a cleaner as well.
When responding to a crime scene, one of the first things police do is check the premises for suspects or other victims. They would not overlook a closet that contained a body. As such, the wife being discovered thanks to the cell phone would not have taken place.