Bring up Wecht at a meeting of pathologists and you can get an idea of how he is regarded professionally.
The ME serves the state, justice. He does not serve the families. He is independent and professional. This one appears to be from what I have read of him. He does not need to have anyone there for "fairness". All his work will be available for anyone else who wants to give an opinion.
All this demanding observors is some lawyer's idea. Brings to mind Johnny Cochran demanding observors at the DNA labs. It is a distraction.
Professional jealousy perhaps?
I read a few articles on this new ME down there, and he sounded like a moral enough guy. But, I'm afraid there is no way for a man in his position not to get caught up in what appears to be a very intricate and ongoing crime. He may have no choice.
Whatever Wecht's motives, and he is said to have been asked by the parents, the ME down there should have allowed the observation, just to keep suspicion off himself.