I've said this for a long time, but there really should be an option for cremation as a deliberate, culturally-accepted means of disposal of the dead.
Burial is a cultural artifact in the West mainly from Egypt (which impacted the Greeks, then the Romans, then Christianity as a whole through them) where it was thought that a physical body was needed in the afterlife. It makes no sense in a culture that should always have believed in spiritual dualism, which the DF world would do, since the DF world has ghosts and the capacity for spirits to leave bodies. Dualism is outright provable physics in the DF world.
In the case of a world where undead rising to eat everyone is a common occurrence, it is absolutely insane for burial practices not to account for this by having cremation or some other form of body destruction be a deliberate act by a culture.
Yes, you can set up manual cremation through wooden coffins and magma flooding the burial chambers, (followed by a slabbing,) but this is a manual override of actual in-game scripted burial practices, not something the dwarves recognize as a deliberate action. We should have the in-game option of setting up crematorium workshops and directing our dwarves to cremate their dead and then slab their fallen as a response to undead uprisings.