Beebo
Guru
We will agree to disagree on the religious bit. Seems hypocritical to me but hey ho.As for the Royal titles, he doesn't get to choose. Grandchildren of the King are Princes and Princesses. Harry is still a Prince. It isn't optional. The only thing he and his wife have chosen to do is not to use the honorific HRH.
Princess Anne never gave her children titles. Edwards children are not princes or princesses either. And their mum was quite high up in royal circles.