I think Landon was a Jew.
Yes, his real (or original) name was Eugene Orowitz.
He was Jewish, not not practicing.
His son (M.L., Jr.) became a born-again Christian as an adult, after his mom took him to an evangelical church. The movies he makes are great. A biography was made of his life, and it detailed his dad’s affair with a makeup artist on Little House set, which broke up his parents’ marriage.