God can and does change people. For Madonna, as you said, would have to go through what is left of RCIA, and that takes about at least a year process, besides the life-long discernment as well. In my parish, 3 canidiates are coming into or being recieved into the Church Holy Saturday night.
I knew an old pastor that had excellent catechists teaching the faith from his own curricula, not the RCIA template. He was replaced by the bishop, and all the catechists were removed and replaced by people who didn't even qualify as average students. The RCIA is a joke. Better to learn on your own with someone who really knows the faith.