The problem is that all of these (except Olivia Riley's grave, which shows up at the art museum) point to a non-existent lot.
There is a community lot called Gamesend Grounds which is obviously intended to be a cemetery, and as Mootilda discovered with her HoodChecker, all the dead sims have urnstone tokens floating around. Long explanation: EA seems to have intended Belladonna Cove to have a full graveyard.
