I'm trying to imagine what a butcher's pit inside (or outside) a house would look like and completely failing. Do you mind you explain more, if it is not too upsetting?
In the livingroom, eek! Is the climate so dry things don't rot? I also wondered that about the buried shirt fabric still having the color recognisable.
Does that cause you problems when you meet a related smell?
Could that explain why they don't want the bones re-tested? You mentioned the initial investigation was incompetent too.
I guess there will be many records of incidents and allegations they were provably aware of. And witnesses to their incompetence or worse, too many for them to cover up. A positive test on the bones would cause further scrutiny.
For that matter, the previous negative result might not be genuine.
Also they might be covering for the child welfare authorities who were supposed to be keeping tabs on you.