Being saved means having been born anew. There is no difference. Same status and blessings apply.
They went out from us because they were never of us means those that depart were never saved, never born anew.
Anyone is not for Jesus is against Jesus, they are thus anti-Christs.
Those that fail to continue were never saved, never born anew, in the first place.
Yes, I see that I did not address one aspect of your argument from 1 Timothy 4:16. Here is the NASB rendering: 16 Pay close attention to yourself and to your teaching; persevere in these things, for as you do this you will ensure salvation both for yourself and for those who hear you.
The second set of misunderstood verses that seem to teach loss of salvation refer to loss of rewards. Once a person is born anew, a new creation created for good words, they earn rewards by their service to Christ. Thus the "loss of salvation" refers to the "loss of salvation's rewards" where we enter heaven "abundantly." If our ministry is lacking or misplaced, we still enter heaven, but as one escaping a fire. Thus for Timothy, a regenerate, born anew, saved person, the loss of salvation's rewards is in view.
Your view that those who pour out their lives for Christ will receive blessing in this world is dubious. I know a missionary, who as a youth (high school or college age) went to the mission field and was infected with malaria. As a result, the missionary has suffered greatly. Clinging to God means we do not inflict unnecessary suffering on ourselves or our loved ones as a result of godless behavior, but there is no guarantee we will not suffer in this life.
Yes, again, professing Christians can and do fall away, like the second and third soils of Matthew 13. But falling away proves they were never saved, never born anew, never regenerated.
Was your reference to Acts 20:18 or 20:28 really a reference to Luke 24:27 or 32?