So, your position is to claim that the two (bystander and the one tied to the track) both act justly in committing lethal acts, one against the other. But the death of anyone is an evil. You claim that the death of either or both at the hands of the other is merely a physical evil. That is, regardless of outcomes, no moral evil exists in the acts of bystander or innocent person. Really?
You justify the bystander by his good intention and justify the one on the track by his right to self-defense. But the right to lethally self-defend is only in the presence of a lethally unjust act. Your position has an internal inconsistency.
Your analysis, I think, confuses the moral meaning of the words “deliberate” and “intention” as if they word were synonyms. They are not. Murder is a always a deliberate act regardless of intention. That is, one murders if one deliberates, that is foresees the act as the means to the death of an innocent person and freely chooses to commit that act. Throwing the switch is the means to the death of the innocent person. (The excision of diseased body tissue is not the means to the death of the fetus.)
1749 … When he acts deliberately, man is, so to speak, the father of his acts. Human acts, that is, acts that are freely chosen in consequence of a judgment of conscience, can be morally evaluated. They are either good or evil.
“Deliberate” means freely, that is the actor could act otherwise. In examining the moral object of an act, the criteria are the foreseeable outcomes and the freedom of the actor to act otherwise. The moral object is always independent of the intention and includes all foreseeable outcomes as deliberate, that is willed. The moral object of an act is fixed for all actors, regardless of any one actor’s good or evil intention.
2261 … The deliberate murder of an innocent person is gravely contrary to the dignity of the human being, to the golden rule, and to the holiness of the Creator. .
Note that the instruction does not mention intention. The intention font indicates the first goal of a particular actor. A particular actor may have a good or evil intention but a good or evil intention does not change the moral species of the act. A deliberate murder can never be justified by of a good intention. The bystander who deliberately throws the switch murders the innocent person.