I started my second tribe and did things a little differently (focused more on research instead of "building" to uncover every secret).
Am wondering if a certain level or puzzle is required to begin recording deaths on the Roster of The Dead and/or marking graves. There is now no record of the existence of Elder Papaya, the first to die! At the time of her death, the Roster was uncovered, but I had not removed all rubble. Only one other villager has died since then, but her grave is marked and her name is on the Roster (rubble removed by by then).
When Papaya died, I did see some villagers on their way to "Burying the Dead", but could not find her bones.
In memory of Papaya, I thank you!