In A Memory of Light, two new factions are introduced:
The Red Aiel and the Sharans.
Are they from Robert Jordan's notes or are they both a Sanderson invention? IIRC, the second faction above are also mentioned in Towers of Midnight?
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For your first group,
Shara is mentioned as far back as The Great Hunt, so they certainly weren't a Sanderson invention.
For your second group,
The Red Aiel weren't directly mentioned, however we knew that the Aiel sent their male channelers to Shayol Ghul. It doesn't take a huge leap to combine that with the knowledge of the 13x13 trick. In addition, Jordan spoke near his death saying "There's a [blank] in the Blight", it is presumable (although unconfirmed) that the blank referred to the town/society that we saw, which heavily revolved around the Red Aiel.
So no, neither of them were a Sanderson invention.