Ok, I give you the backstories, but they do have similar looks and powers - something which is not the case for the two entirely different superheroes named the Atom. I don't think people would think the two versions of Hawkman are entirely different superheroes if they were told their powers and saw them side by side. Then they would just think they were different incarnations of basically the same superhero (like the Flashes). That is not the case, I argue, for Atom. Put them side by side and people would, correctly, assume that they are entirely different.