Who are the Many Mothers in Mad Max: Fury Road?

The "Many Mothers" are actually called the "Vuvalini"... which I personally think is a bit on the nose.

These ladies aren't sex workers at all, they're just an all-female (or at least matriarchal) society.

I'd argue that their closest similarity would be to the Greek Amazons.

These ladies lived in all-female groups and were fierce warriors.

The Amazons (Greek: ????????, Amazónes, singular ??????, Amaz?n), also known as Oiorpata in Iranian and Scythian, were believed to have been a nation of all-female warriors in Greek mythology and Classical antiquity.

The Amazons even had a method of keeping their numbers up... once a year some of the women would go to surrounding areas and sleep with men.

In some versions of the myth, no men were permitted to have sexual encounters or reside in Amazon country; but once a year, in order to prevent their race from dying out, they visited the Gargareans, a neighboring tribe. The male children who were the result of these visits were either killed, sent back to their fathers or exposed in the wilderness to fend for themselves; the girls were kept and brought up by their mothers, and trained in agricultural pursuits, hunting, and the art of war. In other versions when the Amazons went to war they would not kill all the men. Some they would take as slaves, and once or twice a year they would have sex with their slaves.

Either of these methods would be completely within the realm of possibility for the Vuvalini. Clearly Furiosa hasn't been there in decades and much has changed. It's very likely that, before the green place died, it had a significantly larger society that included surrounding groups they could interact with.

Another possibility is that they're not actually anti-men, that they're simply matriarchal and only a very few women were left while none of the men were. It makes total sense that they would be wary of anyone they're not familiar with, as the entire world of Mad Max has gone to pot and everyone is a threat.

As to "initiate mother" I can only guess but it sounds like the sort of thing that implies she was trained and "initiated" into the clan's life and culture by someone other than her mother. It'd be similar to a mentor, someone who's job is to introduce you to everything and help you through all of the trials of learning including fighting techniques, how to use weapons, and other battle skills. I could understand them not wanting to have biological mothers do this as they were probably a source of nurturing in early life whereas this "initiate mother" would be strict and harsh (but supportive), so the child would see them differently.

1) Sex-workers, I don't think so. They do use a woman as a bait. but possibly to rob.

2) During the good times i.e. when the Green Place existed. They were probably non-violent. If you remember during the night scene, an old woman is talking to one of breeder women of Immortan Joe (not sure if it was Cheedo/The Dag-the one with australian accent). When the old woman tells her that she kills with one headshot. She asks the old woman, I thought you were above all that.

3) And yet from the movie, its hard to understand how they breed. Furiosa being daughter of Jabassa, and also having a initiate mother could mean surrogacy but I am just guessing.

The Vuvalini were a matriarchal tribe who lived in the Green Place where they cultivated agriculture for some time.

According to production designer Colin Gibson, they preserved their matriarchal system by keeping male breeding slaves to produce female children while abandoning the males outside their territory to fend for themselves. Those who survived became the Crow Fishers which we see walking on stilts at night within the toxic marsh.

Eventually, for some unknown reason, the land grew toxic, and the Vuvalini could no longer maintain their way of life, becoming the desert-dwellers we see in the movie. I'm guessing that this happened after Furiosa was taken by Joe's men since Furiosa remembers the Green Place existing.

This is just my guess, but since the Crow Fishers had existed prior, and what we see of the Green Place is a poisonous mire when Max and Furiosa unknowingly drive through it, I'm thinking that whatever had blighted the land outside Vuvalini territory, where the boys who would become Crow Fishers were exiled, eventually crept inward to similarly corrupt the Green Place.