If I had never asked my parents what religious background they came from they would have never told me. I don't believe I'm exaggerating. I'm working on a piece where I go into my memory of a generation, many of which wanted NOTHING to do with their religious ("kinship") parents or grand parents. So to answer our question, my mother's conversion wouldn't have been remotely sincere I believe. My father is dead and she's 88 and I doubt will have any more interest in the subject than she had in my 20s ;) If she did she did so to appease my father's Mother.

As you point out, the various forces at work are beyond complex.