There is a Facebook page, mostly debunking Carlos Castaneda and Miguel Ruiz, however only a few posts:
https://www.facebook.com/pg/toltec.bunk/ [Debunking Toltec]
About
This page about debunking the increasingly pervasive myth that the Toltec system of beliefs is based in reality
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22 November 2016
Carlos Castaneda's work was fiction. He laughed all the way to the bank when he realized that people were interpreting it as historical fact. Upon his death Ruiz picked up the torch of chicanery and himself became wealthy propagating the same delusion. There is absolutely no anthropological evidence supporting the myth. People are just VERY gullible and THAT is a fact. Very few among us are critical thinkers. We are far more apt to be mystic dreamers it seems to me.
You will see a couple more posts if you go over there. The site author is named and linked to.
I find it hard to find solid scholarly and academic research debunking Miguel Ruiz.