D&D definitely has at least two components to Prime creatures (elementals and outsiders differ, maybe constructs do, too): body, and soul. Death is a split of these: body dies; soul goes to afterlife.

There is also the mind. Not all things have minds.

I’ve tentatively posited that the soul can be broken up.

There’s also the possibility that “life force” (which liches store in their phylacteries) is a separate component.

The notion of a creature being undead preventing resurrection being due to that creature being not-dead and thus an invalid target for bringing back to life leads to another possible component: identity.

Identity and life force (or animus) might be linked, or might not be. It may or may not be tied to the mind. But if the identity stays with only the body or the soul, And the mind can go with either, you could wind up with identity in the undead mindless body and mind with the soul that suffers loss of identity.

Maybe last rites sends the identity with the soul. And the petitioners who forget all about themselves didn’t get last rites.

You could have an undead soul and an undead body with the mind only with the wraith and not the zombie. But then where is the identity?