Andy, I've read all of the verses you used and many of the others you didn't. My Bible tells me we all are sinners, just some saved and others lost, it all is around what the person did with Christ, did they accept His offer or not.
You didn't answer this: Would you have said David in The OT was carnal or lost in 2nd. Samuel 11, I believe 2nd. Samuel 12 tells us he was saved but carnal at the time of chapter 11. I believe David was out of fellowship at the time but not lost, we know he was a praying man, but at this point of time he was in the wrong place, looking at what he would not have seen if he had either been praying or leading his army. Most all of us have been at the wrong place because we were not doing what we should have been doing, because we were out of fellowship with God at that moment in time. That moment of time could be an hour or less or weeks or even years. How about Peter and his fear, or the person next door, or me, or how about yourself?
I was told right after I got saved, that you don't know how bad you can hurt until you have been cheated or lied to by a Christian, I found that to be very true. I've seen Christians act very bad to other Christians and I have seen preachers speak untruths about other preachers and so on. Keep in mind we have a battle going on at all times, we have the Holy Spirit, the natural man or old nature and self and at times we follow the wrong one. I believe pride is our down fall and man have I fell many times due to pride, said things with the wrong attitude at the wrong time.
Look at Romans 7:15-20. This is the conflict of two natures, the old nature and the new nature. Paul’s sinful human nature influenced him to such an extent that he found himself volitionally doing the things that he despised. We all can identify with him. He is telling us that sin had thoroughly corrupted his nature the flesh. Even though he was a Christian he was still a totally depraved sinner as we all are, check Ro. 3:10–18, 23. He knew what he should do, but he did not always do it.