You're right, that's a whole lot, and most of it seems logical. For some counter discussion, more hypotheticals.
Din was raised on Concordia during the Clone Wars, right? Maybe sometime after the Empire took over his group left, giving no reason for the Empire to bomb it as well. Or maybe, as Bo-Katan said, they left after fighting with her over control of Mandalore. Either way, I agree the armorer is pretty suspect. I think it's possible that she doesn't know truth about Mandalore, I can't see any reason why her group wouldn't just go back and try to make a living if she knew it was fine...especially after the fall of the Empire.