>A love and selflessness religion that is usurping the govt.'s
>official religion?

He isn't trying to usurp the official religion and isn't practicing a new religion, as he still worships the 7. The High Sparrow is trying to reform the church and actually apply its teachings to help the poor and powerless. He is more of a Martin Luther figure than Jesus.

>I wouldn't be surprised if Cersei converts.

She doesn't seem like the religious type. She will use religion to help her position of power and eliminate her enemies but just because she like to drink wine doesn't mean she is coming to church on Sunday's.