I've put this in the lighter side section which should be a clue.
For a child who has died, parents sometimes list the names of surviving siblings. Those siblings are living minors, so publishing their full names in an online grave index or even in a cemetery could bring GDPR into play.
SECONDLY WHILE THE STONE IN ITSELF IN A CEMETERY IS PUBLIC TO ANYONE WALKING BY, ANY SCANNING, INDEXING AND PUBLISHING GRAVE DATA ONLINE, IF IT INCLUDES THE NAMES OF LIVING FAMILY COULD BREACH UK GDPR REGULATIONS. Sorry, caps off.
Zaph