I think you are missing the point.
The idea of "death" is one that you are first dividing. Death in this case is more then encompassing physical death. From the Greek paper I wrote on this text, I summarized (I do not think the Greek words will come over in this response, but I can hope):
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The second word that comes into discussion is “death”. Like “world”, this word has a variety of meanings to include: physical death (Luke 2:26), spiritual death (John 8:51), but also being in imminent danger of death (2 Corinthians 4:11-12). The obvious reference, though, of Romans 5 is to Genesis 2:17 and 3:19 because of the use of Adam and the idea of sin entering this world.
Wayne Grudem relates what is meant by the word “death” in Genesis, “death, most fully understood to mean death in an extensive sense, physical, spiritual, and eternal death and separation from God.” Dr. Grudem is correct. The death mentioned encompasses the physical; man decay. Death encompasses the spiritual; man is dead in sin. Death encompasses the eternal death/separation from God; man was banished from his original state in the garden and sentenced to the second death, hell.
The verse further clarifies death, according to Moo, “Paul’s concern in this verse, and throughout the passage, is not with “original sin” but with “original death.”” The sin of Adam resulted in death (5:12a) but, after death took hold of each individual man, death will result in man’s sin. Cranfield says, “the result is a chiasmus—sin, death, death, sin.” To put it more plainly, Adam sinned therefore all have died but because all have died, all sin. The first part of verse 12 deals mainly with the entrance of sin into the world. The second part of this verse deals with the penetration of sin to all mankind.
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This text shows that we are dealing with eternal death that spread from Adam to all people. I think the full view of death demands that Adam's sin did radically infect man throughout. The chiasmus is rather clear in the Greek text and I believe it is irrefutable. Thus, death itself is the imputation of the sin to all mankind, which is also the imputation of death to all mankind.
Let me quote again from my paper:
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Which brings this paper to the nature of sin. Is the sin mentioned here the actual sins of men or representative? The answer in verse 12, “in that all sinned” (Greek, “ἐφ' ᾧ πάντες ἥμαρτον”, eph w pantex hamarton).
While others will reference Romans 3:23 and 6:23 and believe this sin is merely the actual act of sin by all people, Paul notes that not everyone sins after the likeness of Adam’s sin (v. 14) thus this is brought into doubt. As a result, this could not be merely the actual likeness of sin of Adam.
Many commentators believe that death is caused by each person’s own individual sinning. This interpretation, as already discovered, is not accurate. The context, though, helps to clarify the context in v. 18a. Some commentators believe the sin, in this section, is a collective sin (Augustine) and not an individual sin. Hendrickson objects to the collective sin idea of Augustine when he says, “Why should ‘all sinned’ mean one thing (actual, personal sins) in Romans 3:23, but something else in 5:12?” . Douglas Moo even points out that the aorist tense of “sin” is almost always used of actual sin .
Yet, Dr. Moo does go further to explain the representative nature of sin from the Old Testament. Dr Moo states, “This notion, rooted in the OT, held that actions of certain individuals could have a “representative” character, being regarded as, in some sense, the actions of many other individuals at the same time.” Just as Jesus’ righteousness is imputed so is Adam’s sin imputed. This is what Paul has in mind, showing that death leads to sin and the imputation of Adam’s original sin is imputed to all people. The context seems to demand a representative nature of sin, which is imputed to all men without distinction.
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Moo makes a compelling case that while sin in the aorist tense does have an individual nature, he notes that v. 18 demands a representative nature. I think it is clear that Adam's sin is as though we personally and individually sinned in Adam. He was not just our representative, but we actually sinned in Adam.
You mentioned that we must believe by faith, but you mistake the nature of grace mentioned in this verse. Let me quote from my paper again:
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The emphasis on grace is that it is a free gift. John Murray makes the point, “The construction here would indicate that the grace is that exercised by Jesus Christ and not, in this case, the grace of God mediated or issuing to us through Jesus Christ” (emphasis by John Murray) . In other words, here the emphasis is on Jesus’ exercising grace to those who are dead in sin.
There is a difference in the use of the word grace as seen in the two words used: δωρεὰ (dwrea) and χάρις (charis). Some have suggested a distinction between the two. They suggest δωρεὰ as a general grace to all (also known as common grace) and χάρις is grace to only believers. Yet, this is a stretch. The former is likely to signify motives or manners while the latter is the specific manifestation of grace. Thus, by verse 16, one sees in this context that sin of one person required another person to die, not for that one sin only, but for all the sins of all the Christians of all Centuries.
When coming to verse 17, the text is similar in construction to that of verse 15, which also includes a conditional clause. The text explains the reign of death was brought about through one trespass and the reign of life through the one, Jesus Christ . The phrase “much more” comes to bear her weight in this verse as well. Grace, then, is seen as being greater than all the sin including the sin of Adam. The verse seeks to point us to the generosity (δωρεὰ) and provision (χάρις) from God.
Morris notes, “With grace Paul links the gift of righteousness.” This phrase is forensic, the person stands as righteous by a means of earning such a position, not by their own merit but by Jesus’.
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In other words, you are placing faith upon the person, but grace here is what proceeds from Jesus to his elect people.
You mentioned the universality of the condemnation and I spent so little time on this because there was little debate on this issue except by universalists. Here is the brief statement I did make
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This brings the text to a point where the phrase “all men” as used of both death and salvation. Is the phrase “all men” when referring to sinners the same as “all men” when referring to those who were made alive? Some modern scholars do take this verse to argue for universalism. This, though, is unnecessary because clear teaching elsewhere demands that the Bible student believe not all will be saved. Even in this text (v. 17), Paul is clear that here is a limitation of salvation to those who are His own. What is the proper translation? Mark Dever points out, “The curse and contagion of sin spread to all nations, so the good news of salvation by faith in Christ Jesus is meant for all nations as well.”
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Thus, the “all man” was addressed a couple of times in the paper, with the conclusion and emphasis is not upon the individual nature of man but upon the corporate or national nature. This is so readily agreed upon by a myriad of scholars that I felt it was a waste of time to deal with the issue in Romans. Unless you embrace universalism, you must embrace this idea. Thus, sin spread to all mankind and grace spread to all mankind. While “all have sinned” because of Adam, and previous sections of Romans deals with each individual person, this is more of a corporate declaration.
