On who can be a member of the Church
"A person becomes a member of the Church through baptism. Therefore, children also are members of the Church, and it would be wrong to say that only ‘the faithful’ or appointed are members of the Church.
For both the righteous and sinners equally can be members of the Church, even those God foresees will never reach salvation because of their sins. But beyond the publicly baptized, there may be people who are meant to be saved and those who have God’s grace and who will surely reach salvation. "