Tom: You can be the rudest, most evil bastard on the face of the planet due to some chemical imbalance like alcoholism, and you could still be Heaven-bound because your soul has accepted salvation.
......
Tom: In Catholic dualism, your essence is distinct from your materia, and in fact your materia is not an indicator of your essence. This is why wafers and wine do not perceptibly, materially change to flesh and blood, but they are believed to be in essence -- in their, real, true, spirit -- transformed. In the same way, your physical body and your physical mind do not reliably express indicators re: the state of your soul, and vice versa. They can be linked, and indeed many Catholics verge on heresy on this point because it is so difficult to imagine that they are not more strongly linked than doctrine establishes, but you can have a good and repentant soul while performing evil actions if the materials of your earthly existence prevent your soul from properly expressing itself (and vice versa; you can do only good actions and believe you're doing them for good reasons but your soul might not be truly repentant.)
You're using words in a way that Catholics don't, so it's pretty hard to figure out what you're trying to say. I think you're misunderstanding Catholic doctrine and then extending it badly from that misunderstanding. I'll try to respond point by point.
"Good" or "Evil" as a property of the essence: This is the big mistake you keep making in your rendering of Catholic ideas. A person's essence is not good or evil. "Good" is not the answer to "What is Josh?". I may do good acts, I may do good evil acts. But
what I am is human.
Transubstantiation: The change of the substance of bread and wine into the body and blood of Christ is a supernatural phenomenon. (Note: it is not transformed as you say; that means something else entirely). This is a mysterious act by God. It is not in the nature of bread and wine to substantially change into body and blood. It is not in the nature of a human to be able to change bread and wine into body and blood. It is not natural for flesh to have the appearance and accidents of bread. This is supernatural. It is an effect produced by God exceeding the power of the created universe. Extending this supernatural phenomenon to speak generally about the natural world is not reasonable.
The material body's relation to the soul: The soul is the form of the body and the first principle of life. Form means "that which makes a thing the kind of thing it is." The form is the organizational pattern that unifies and coordinates the parts of the human body. The soul is intrinsically linked to the matter of the body; they are not two separate things in the way that you are suggesting. I tend to believe they are unified as outlined in the
hylomorphism of Aquinas (although the Church hasn't committed to this exact metaphysics).
Excluding supernatural effects, the form of a thing and its matter are closely linked, and it does not make sense to speak of them as existing separately or being two things put together. That is to say, the form is not a separate substance than the matter (like a ghost living in a machine) but rather the soul and body together make up one single substance. (
More details here).
Matter is potential, form is act. The two unified together make a thing. There is not matter as a substance without form, nor is there (naturally) form as a substance without matter. The two are deeply joined and form one single substance.
Grace and the soul and the body: Grace is not a property of our soul. When a king's grace grants life to a criminal condemned to death, the nature of the condemned criminal doesn't change, only his relationship with his King. That is to say, he doesn't change substantially from a "condemened person" to a "person", he's always just been a person.
In the same way, when God grants us grace, our soul is cleaned of sin but it is not substantially changed. You keep trying to make "grace", "good", and "evil" properties of a substance. It doesn't work like that.
Freedom to act: As I mentioned above, to any degree that your acts are not your own but rather forced upon you by some external cause, you are not guilty of sin. Sin is a voluntary action of the intellect and will. If they are fully disabled, then whatever someone or something else does with our body has no bearing on our own sinfulness. If you are unconscious and I use your hand to pull a trigger and kill someone, you aren't guilty of an evil act. A natural evil occurred (the death of someone else) and I am guilty of sin. It doesn't make any sense to say "Tom is an evil bastard" because I used your unconscious hand to assist me with a murder.
You can't say a man is "the most evil man on the planet" and "is heaven-bound" as you did in your first post. The two are contrary terms. The very best thing you could say is "a person could do seem to do evil acts that were not in fact evil, due to some mitigating facts or circumstances." Of course, if you said that, you could not call that man "the most evil man on the planet".
Tom: But you can have a good and repentant soul while performing evil actions.
This is a restatement of your original proposal, and it is still wrong.
1. It is nonsense to say you have a "good soul" or "repentent soul" for the reasons outlined above. You have a human soul. It doesn't change
what it is based on how you act.
2. You cannot be repentant for an evil act which you are currently performing. Repentance can only come after an evil act. Repentance is a turning of the mind and will away from sin and back towards God. If you are currently performing an evil act (which necessarily implies you are willing that evil act) your mind and will are oriented towards that evil act. They cannot simultaneously be turned to God and towards evil.