the fiction that we only need the head to 'reanimate' a person back to normal is just that, fiction.

Well, it might be a fiction in the sense that we never actually do it. (Personally, I doubt there will ever be star-trek style teleportation for macroscopic objects, even though it seems 'possible in principle'.)

But I think the OP is asking about the possibility in principle of restoring a dead person such that their memories, personality and intellect remain intact. If a frozen body has 'enough information' then so does a frozen head, right? Seems pretty uncontroversial, but as the OP points out, there are people who disagree.