Yes she was Mother.... As far as I'm aware The Mother isn't OC. The Son, Father and Daughter are of course. That would be a cool thing though if Snoke was the Son hell bent on revenge against the Skywalker lineage.
Perhaps, but Abeloth was. She is in two parts of the Fate of the Jedi series, where she tries to tempt Ben Skywalker and someone else to drink of the Font of Power and become the new Son and Daughter.