The Bible says no one can say Jesus is Lord without the Holy Spirit. Catholic Christians believe and profess this, just as all other Christian denominations, so we are Christians too:
"Therefore I want you to know that no one who is speaking by the Spirit of God says, “Jesus be cursed,” and no one can say, “Jesus is Lord,” except by the Holy Spirit." (1 Cor 12:3)
St. Augustine wrote long ago:
"By God's Grace and Christ's Favor we are Catholic Christians." This was the way the Early Christians referred to themselves. St. Ignatius of Antioch (died A.D. 107), after the Apostles' Creed, was the first to use the term "Catholic Church", which means "Universal Church - or Church in every nation"
(see Rev 7:9).
Anyway, Bible also says if anyone confesses Jesus Christ is the Son of God, God dwells in him, and He in God. We do this, hence God dwells in us:
"15If anyone confesses that Jesus is the Son of God, God abides in him, and he in God." (1 Jn 4:15)
Finally, the notion that the Catholic Church is Anti-Christ is laughable, and contradicts Scripture which says Anti-Christ cannot confess the Father and the Son, i.e. the Trinity, just like he cannot confess that Jesus Christ is Lord, which only those who have the Holy Spirit can confess:
"22Who is the liar, if it is not the one who denies that Jesus is the Christ? This is the antichrist, who denies the Father and the Son." (1 Jn 2:22) Does the Catholic Church do this? Nope. Islam does do it.
Will get back on the Saints in Heaven later. As mentioned, it's not correct to refer to Living Saints in Heaven as "dead". That's what the Sadducees did, and Jesus Christ corrected them, by saying God was the God of the Living, not of the dead. He showed by that statement, from the only 5 books the Sadducees accepted, the Pentateuch (source below), that God, who had declared Himself the God of Abraham, Isaac and Jacob, in the time of Moses, that Abraham, Isaac and Jacob were living Saints in Heaven. The Sadducees erred on this issue in part because they rejected many later books including Maccabees which clearly explain the Truth of the Resurrection already in Old Testament times, as well as of Angels and of Spirits/Living Saints etc.
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The Sadducees refused to go beyond the written Torah (first five books of the Bible) and thus, unlike the Pharisees, denied the immortality of the soul, bodily resurrection after death, and—according to the Acts of the Apostles (23:8), the fifth book of the New Testament—the existence of angelic spirits."
https://www.britannica.com/topic/Sadducee