‘I’m thinking more about the pillow over his Justice Scalia’s head. If he was purposefully suffocated, there would likely be some evidence of this.’
Nope, no autopsy needed. Suffocation is easily detected without the need to cut him open.
It depends, and sometimes micro hemorrhages and other findings on tissue examination are helpful/necessary. Also, the ‘autopsy’ would include those findings that you’re referring to that wouldn’t require an invasive approach.