Nice find! This controversy is accurately described as a play for public sympathy by alleged "victims of prosecutor abuse," but it may also involve the defense legal strategy.
We know Fisher-Byrialsen would like to argue that the autopsy results should be thrown out - or at least doubted by the jury - because it was corrupted by the influence of the people Morphew sued, some of whom were present.
We also know from the article you found that the daughters were advised by "their" attorneys not to retrieve Suzanne's remains.
Why would it be in the daughters' legal interest to put the funeral on hold? Why does that interest no longer require preservation of Suzanne's remains?
It seems obvious that the daughters wanted to protect their father's legal interest, and that the remains needed to be preserved until the defense attorneys could review all the discovered evidence and consult with their own experts about the potential usefulness of a defense-oriented autopsy. If it would likely contradict the coroner's findings, they would need the remains as evidence. Of course, if it affirmed the state's findings it would eliminate their ability to question them.
It appears that they have decided a defense autopsy will not help Morphew, and they have so informed the daughters.
I wonder if the defense attorneys also believe they can hamstring the prosecution by destroying the remains before disclosing how they intend to attack the state"s autopsy. Without the remains to test, the prosecution's ability to rebut the defense attack with further expert examination would be limited.
All MOO and speculation, of course.