The Witch Warriors mention that creating Diana from clay involved pottery. In her usual depictions, while Diana was being created, her mother Hippolyta (and her other parent, if any) breathed life into her. Pottery involves using your mouth to blow air at the glaze, and since we know that the Aura of fellow Artificial Human Penny came from a piece of her father's Aura, it's likely that Diana's Aura is composed of various pieces of the Witch Warriors — hence, why she calls them her "mothers" as opposed to only calling Hippolyta her mother and calling everyone else her sisters or aunts like in most depictions.
The Witch Warriors are an ancient society of Faunus women who live on Bird of Paradise Island, an island hidden away from the rest of the world. Considering that the Witch Warriors are the equivalent of the Amazons, it's not unlikely that they hid from Remnant to avoid discrimination for being women and Faunus.
This also explains why they made Diana to look outwardly human, to avoid her having to deal with anti-Faunus Fantastic Racism.
Despite the numerous inconsistencies, the comic is stated to be canon. Then comes Issue #9, where we learn RWBY is part of a multiverse, so in a way, RWBY/Justice League is canon, but not to the show's canon. After all, this isn't the first time that RWBY has interacted with a franchise with tons of timeline shenanigans.
