The bare neutral enters a two-gang box. It is connected to the normal white neutrals inside the two-gang, with the exception of the white that is tied to the blacks (the white being the home run ungrounded conductor.)
Everything
looks exactly as I expected it to, when I looked in the panel and started thinking about what I might see. It looks like the black opened, and they moved the white to take the black's job, and then left the ground on the ground bar but started using it as a neutral in the two gang.
I'm just trying to think of another theory about what's there before I reenter the unit and starting tearing things up. It's kind of a rhetorical question, since it's coming out anyway, but if these symptoms are telling me that my mental picture isn't right (which I know it's not), then I might miss something.
Not a reduced size, and no I won't.
Just to give you some more heartburn, I happened to open an access panel and find a splice with no box today, and I just wrote it down.
Thinking about that more, there are no 30A circuits in the building, and the splice was 10-2 NM. That means it's probably coming from the house panel on a building central to the project, and is not disconnected before entering the building, which is another violation...