1/ Here’s a thread on traditional catholic group SSPX (Society of Saint Pius X) and its ties to various far-right groups. This might take a while, it’s not quite Christian Identity levels of intersection but it’s a lot.
2/ SSPX has over half a million followers worldwide and there are probably a whole lot of reasons why people get involved with it that have little to do with fascism, but also there’s some that do.
3/ SSPX was started in 1970 by Archbishop Marcel Lefevbre of France in response to modernisation of the Catholic church and the Vatican II reforms. I’m no theologian so I’ll leave that stuff aside. Pic of Lefevbre with Irish President Eamon DeValera.