The concepts of a triple moon Goddess or of the Maiden/Mother Crone concept are.modern ones that is unrelated to historical religions. It was largely the creation of Graves in his book of poetry called "The White Goddess". Gardner took this idea and incorporated it into Wiccan practice.
For instance, in the construct you are working with of Artemis (Maiden), Selene (Mother, and Hecate (Crone) has no relationship to ancient Greek practices. Just to point out one inconsistency between ancient/modern viewpoints, Hecate was a Titaness, not a Goddess; and she was a young woman, not the Crone.
There are some triple Goddesses in other ancient religions such as Irish mythology with Brighid and The Morrighan, but they do not fit into the Maiden/Mother/Crone construct at all.
Be very careful when trying to stuff ancient deities into modern pigeonholes as they often don't fit.