Are Non-Catholics Members of the Church?

There is what I consider to be 'formal' and 'informal' communion with the Body of Christ. A man in formal communion is a member of the Body, and the man who is in informal communion is a mere subject to the Body. This is Pope Pius XII on ecclesiastical membership:

          Actually only those are to be included as members of the Church who have been baptized and profess the true faith, and who have not been so unfortunate as to separate themselves from the unity of the Body, or been excluded by legitimate authority for grave faults committed. “For in one spirit” says the Apostle, “were we all baptized into one Body, whether Jews or Gentiles, whether bond or free [Mys. Cor., 22].

Since those who are called members are orthodox and non-schismatics, that makes those who are only subjects heretics and schismatics. One is made subject through the "indelible effect...in...Baptism [CCC 698]." Any validly baptized person who repudiates the truths taught by the Church is in informal communion with the Body, while a person who is both validly baptized and accepts the truths taught by the Church are members. Moreover, I would not consider an unrepentant sinner who accepts the teachings a member, for he does not carry his cross daily (Lk. ix. 23).

Prayer for the Informals: Our Father in heaven, lead those who are not members of Your Body to you, so that we may be one as You and the Father are one. This we ask in the name of the divine Word, the King of Kings, God the Son. Amen. Blessed mother and all the saints, pray for us.