What exact rights might DC hope for past-Action Comics #1?
I would presume DC might try to make an argument that their work on Superman past Action Comics #1 was different enough that it could stand on its own as independent work (particularly the post-Byrne reboot), and not subject to the Siegel’s copyright. The Siegels, of course, will argue it is all just derivative of Action Comics #1. This would also be determined by a jury, and since it would be by a jury (and this case likely will never see a jury), it really is not a big deal. That is strictly a “Do we have to pay them for this stuff?” question, by the way, not a “Hey, they don’t own Superman! We changed him enough!” thing.
