Just some short replies:
People are judged according to the light that they have: the greater their knowledge of God, the greater their responsibility to put that knowledge into practice. That is what Jesus means in Luke 12 when he says,
“The servant who knows the master’s will and does not get ready or does not do what the master wants will be beaten with many blows. But the one who does not know and does things deserving punishment will be beaten with few blows. From everyone who has been given much, much will be demanded; and from the one who has been entrusted with much, much more will be asked."
And as you see from the context, “hell” is not the same for everyone, for Jesus hints at degrees of punishment, just as elsewhere he hints at degrees of reward. What exactly this might be is not defined for us, but what it says to me is that eternal destinies are not necessarily a binary assignment to heaven/hell; rather, God’s judgment seems to involve some sort of continuum. Still, it is hard to imagine what that might involve, so I’ll leave my speculations at that.
This is a common understanding of Jesus’ statement in the Sermon on the Mount, but it is not the best translation of the Greek. Here’s what D.A. Carson said in his commentary (with rough transliteration of the Greek):
“The second auten (”[committed adultery] with her") is contrary to the common interpretation of this verse. In Greek it is unnecessary, especially if the sin is entirely the man’s. But it is explainable if pros to epithymesai auten, commonly understood to mean “with a view to lusting for her” is translated “so as to get her to lust.” The evidence for this interpretation is strong. The man is therefore look at the woman with a view to enticing her to lust. Thus, so far as his intention goes, he is committing adultery with her, he makes her an adulteress."
In short, here is how Carson might translate Jesus’ words: “You’ve heard their interpretation of what was said: ‘You shall not commit adultery.’ But I say that whenever you let your eye linger on a woman to entice her to lust after you, both of you already have committed adultery in your thoughts.”
Frankly, I don’t understand your worries about what the biblical authors (OT and NT) may or may not have believed about the physical world. It is a bizarre recent twist to the doctrine of inerrancy.
It does not treat all disease that way. This is similar to your previous question, because the root of both problems can be traced to the fact that God’s message is timeless, yet it is timebound in the sense that it was delivered to specific people in a specific culture at specific times and places in human history. We cannot escape that fact, and no amount of logical backflips can erase these traces of history from the ancient collection of literature we call the Bible. God has always had to “meet us where we are,” even though the target keeps moving.