It seems these memorial portraits became A Thing in Iceland and Denmark in the 17th and 18th centuries, portraying the dead with their families, in a religious setting. Here’s the late District Commissioner Pétur Þorsteinsson with his wife and their children. His sons all posed for the artist, but the women were all done from a single model. The six babies on the ground are children they lost early. Which is sad but also super convenient that they added up to 12. This seems to be the number you want for these types of paintings.