Israel faced this problem after they hanged Adolf Eichmann. They cremated him and dumped the ashes in the Mediterranean.
When the Soviets overran Hitler's bunker, they burned his body for the same reason.
After the US executed that Paki who shot five CIA officers as they approached the entrance to CIA HQ, they were not so wise. They returned his body to relatives. Thousands gathered at a stadium in Quetta to honor the fallen "soldier of Islam". Deroy Murdock at the National Review has a better idea: Bring back General Pershing's mode of disposal.
So I propose a compromise that should give everybody at least some of what they want. Smear them with the pig matter, feed them to pigs, then send the collected feces from those pigs to the families, along with video of the entire ritual. For the families, it would be the next best thing to being there. And they would also have something to place on the mantel.