Sami-folk / Tribes tended to bury their dead in stone mounds, often wrapped in birchbark.
In the southern parts of the North, dead were sometimes cremated. Sometimes buried in ground, sometimes in stone mounds, and often people that were hostile, buried in bogs.
One of my characters disposed a gang of 4 vagabond robbers, and as he went to bury them the following night, found the remains to... float. (if needed, some tying equipment and stone should help with submersing)
Suggestion, allow varied burial types for deceased.
1) pushing or throwing remains in water in open mire and pine mire to be "buried in bog" similar to metal items.
2) add tile-gfx for burial mound, constructed with remains and 15-20-ish stones *
3) adding items in dug pit, then filling the pit; leave the items in the ground, not pop-up on the surface
Cremation/burning remains already works
* adding some mounds in proximity to villages would add touch of realism, deepen immersion. And in case of hired help dying, carrying, or dragging the remains back to their home village could allow proper burial.