This is where I have a problem with an RDI. If the parents are going to stage her body in the home they are going to look more guilty than ever if a RN is found.
The killer could have not written an RN and that would have made the parents look guilty.
If guilty and having some time to dispose of the body they are in a better position to claim their daughter was kidnapped before being murdered. The body being found at the home could not have been the plan if an RDI is true.
They are going to be prime suspects with or W/O a RN.
The kidnapping would be more plausible had they gotten rid of the body.
The body being found at home doesn't seem like a good plan, but consider that they had a houseful of people by 7am on that fateful morning. The plan could not have been to dispose of the body at a latter time - if that were the case, they'd have called the police, and only the police, and hoped the cops didn't hang around too long.
To me it seems the only reason to throw an early morning, come as you are, JBR has been kidnapped block party, is the hope that someone would wander around the house and find the body. IMO getting rid of the body was no longer on the agenda (if it ever was) once all those people were called up.
Of course, we may be seeing the aftermath of shifting from plan A to plan B to plan C. Some of the changes may have been bilateral, some unilateral.