Regarding the "refusal" of the autopsy, it's accurate to say it's the coroner's call, in the sense that the family can refuse it and the coroner can override that refusal. So, the family didn't ask for an autopsy (or outright refused one), and the coroner didn't see cause to override that and order one.
These are the sheriff's words from his previous interview (uncut footage on YouTube, and this is within the first two minutes of the interview). He's talking about the morning of Tammy's death, after the officer responded to the home: "…Contacted the coroner, coroner responded, and body was transported to the funeral home. The coroner went there also, to do a further examination, and she determined that there was nothing out of ordinary…natural causes. A few days later, we started getting information out of Arizona that we maybe ought to take a closer look at this. As a result of that, we got a court order in December and had Tammy’s body exhumed and an autopsy was performed by the medical examiner in Utah…"
So, the coroner did a further examination and determined an autopsy/investigation/inquest wasn't called for. But, this is also on the heads of the sheriff's department, because an unattended death of unknown cause is in their hands to investigate and provide a written report of the investigation to the coroner. So, the sheriff's department investigation, to what degree one was done, also informed the coroner's decision about autopsy/inquest/further investigation (see 2 and 3 in section 19-4301 of Idaho code here):
Section 19-4301 – Idaho State Legislature
Interesting info here from the CDC about Idaho, as well:
Idaho - Coroner/ME Laws | CDC
