RE: Asgardia – Yes, it involves Oklahoma and the storyline reason is too stupid to get into. But basically, Asgard fell down to earth and now floats over Oklahoma and they renamed it. The real reason though, “Asgard” is public domain and can’t be trademarked by Marvel. Asgardia totally can be.

RE: Zatara: Yes, the Zatara that currently appears is Zatanna’s cousin, and the original Zatara’s nephew. But they’re both based on the original Zatara (Zatanna’s father). Zatanna debuted in 1964, but Zatara debuted in 1938 in a comic called Action Comics #1 that was more or less unmemorable otherwise… well…. except for this one guy…