“Are Catholics, Methodists, Lutherans, Episcopals, etc., all false Christians?”
The Bible doesn’t mention “Catholics, Methodists, Lutherans, Episcopals,” etc. Instead, the Scriptures simply have two categories for humanity: the “just” and the “unjust.” The “just” are those whom God has justified (made right with Himself through their repentance and faith in Jesus). The “unjust” are those who are still in their sins. The Bible warns that God will see that every wicked person gets exactly what he deserves: “So it will be at the end of the age. The angels will come forth, separate the wicked from among the just, and cast them into the furnace of fire. There will be wailing and gnashing of teeth” (Matt. 13:49,50). That’s good news for those who care about justice.
So the question is, how is a person “justified”? The Bible says that we are freely justified by God’s mercy. We are guilty criminals, but God acquits us from the courtroom because Jesus paid our fine. Everlasting life is a free of God (see Rom. 6:23). No one has to be “religious” to try to earn salvation from death. So who are the true Christians? Here is the Bible’s answer: “Nevertheless the solid foundation of God stands, having this seal: ‘The Lord knows those who are His,’ and, ‘Let everyone who names the name of Christ depart from iniquity” (2 Tim. 2:19). So make sure you are the Lord’s, and that if you name the name of Christ, you depart from iniquity (violation of God’s Law).
Acts 24:15 I have hope in God, which they themselves also accept, that there will be a resurrection to the dead, both of the just and the unjust.