Hi Goober,
Yes, I believe in "original sin," if by that you mean that our first parents gave ear to the devil and willfully subjected themselves to sin, death, and the curse, which has brought upon us corruption in all our ways and a loss of excellent gifts which we had once received from God, other than some small traces. (I paraphrased from the Belgic confession, article 14.)
For your second question, we need to step back, because I disagree with an assumption that shows in the way you worded the question. I don't believe there is even a such thing as a "good person" outside of Christ. So... unless one is saved through faith in Christ, they will be eternally damned. Hence, the urgency of evangelism.
Third question is combined with the second. We are eager to spread the message of Christ. Perhaps it is possible for God to illumine the hearts and minds of people in remote places via some method other than the Bible and the preaching, but such illumination, if it were unto salvation, must necessarily involve an awareness and embrace of Jesus the Christ. They DO NOT need to know how to spell or pronounce his Greek name or his Hebrew name. But they need to know him personally as the Son of God, and as their substitute. In a manner of speaking, the believers in Old Testament times were less enlightened than we are, for they had not the privilege of knowing the mysteries of the fulfillment of the prophets. However, we Christians believe that many of them are saved, though in their lifetime they never heard the name "Jesus." They were saved through faith in this same Christ, though. They looked ahead through the prophets, we look back through the apostles, but we're all looking at the One Christ.
Capital punishment: a fair trial that sentences death upon a murderer is a just and fitting punishment. It's not merciful, but it is just. Justice is always righteous, even when we prefer mercy. The sentencing of criminals makes me cringe, and I do have a prayer that such men and women will have a second chance. One thing I know is that, though guilty and punished in this lifetime, many of these criminals will yet be eternally glorified because they embraced the Righteous One who laid down His life for the unrighteous, and so their sins were nailed to the cross with Him.
How do I define hell? It is eternal suffering under the wrath of God. It's not merely the absence of God, but it is the presence of his divine wrath. I do not know the details of how that looks or feels, but I am certain it is the most unpleasant thing beyond our understanding.
What are your answers to those questions?
Thank you,
Paul