I'm no legal expert, but it seems to me that any company basing their ownership claims, licensing claims, and actions on an agreement with a company that no longer exists is most likely no longer valid. I believe that here in the U.S. an agreement between two business entities is considered dissolved when either one or both of the entities no longer exhibit their interest or no longer exist as companies.
Perhaps a bounty should be created to pay for a lawyer who in turn would file a petition on the behalf of the "Amiga Community" claiming rights to the ROMs. I'm sure the right lawyer could talk stuff like "in the best interest of humanity, infringement of rights, collusion, Eminent Domain, Magna Carta, Manifest Destiny, etc".
If it could be shown that the "Amiga Community" is a class (and i'm sure that it is in some way) then maybe this could done as a "Class Action" lawsuit. It seems like rulings in these types of cases almost always favor the class.
Maybe a ruling or agreement could be reached where all members of the class would receive two new ROMs or a CD-ROM with ROM files for every Amiga that they have. (As if that would ever happen, I'll bet no company would step up to claim ownership if they knew they might have to supply a bunch of ROM chips or CD-ROMS)
If nothing else, the whole issue could get tied up in the courts for years until all of the current entities claiming ownership fold up and disappear. This would leave ownership even more impossible to resolve, dispute or refute. I'm sure some more posers would show up to fill their shoes and to claim their non-existent rights.