Assuming it continues to be tried under Utah courts, their best bet would be to argue the “aggravated” part of the charge (if they can’t win outright). It seems that without it being “aggravated”, they can’t seek the death penalty and can look for a shorter sentence of mininum 15 years.

In any case, a guilty verdict on murder would be a long time in prison even with the minimum sentence, and it would be tough to argue for it to a judge in Utah.