I like the attempt at the subtitles! I think the direction you’re taking is definitely a clever way to try to improve or support what is already there in the film. I do wonder if the audience would be confused by the Stormtrooper calling him a janitor, since it isn’t really touched on again until the third act. The way I understand it, Finn was a First Order/Stormtrooper ensign who was assigned to maintenance duty until he was promoted by Kylo Ren for whatever reason. Before the First Order was in any kind of conflict, I imagine a lot of their child-soldiers were being used as labor, so the logic makes sense to me. I just wonder, to a first-time viewer, if these additions would be more confusing than clarifying, you know? Like, is there enough context yet that connects all these little details? Because you’re still left wondering why Ren promoted him.

I wonder if Kylo’s line, “The one from the village, FN-2187” could be changed since in this version of events, Kylo would’ve been familiar with Finn before the village attack. You’re obviously pretty limited by available dialogue, but there might be a way you can alter this line to also help support this idea you have.

As far as the dialogue you’ve written, I think it sounds really good though. I can imagine hearing it and it fitting well.

EDIT: Maybe he could say, “Ren should have left you with the trash, like the captain wanted.” since, “let you rot in the trash” might be more ambiguous, like they wanted to kill him or something.