I mean, Antlar and Miclas exist in the Marvel universe (though the handbooks claim they are extradimensional) and Godzilla exists as well, so I don't see how Ultraman can NOT fit... Assuming this even takes place in the Marvel universe.
Don't see why it being issue #1000 is a negative at this point. DC's done One Million, various comics do issue 0's after issue 1's. Seems like a silly thing to complain about. Though your review still, somehow, got someone to not read the comic, so congratulations?
Either Mysterio's lying, the trailer's lying, or a simple case of (in-universe) misnumbering. Not the first time a reality has been misnumbered. Also, to those thinking they changed it to 616, that's actually impossible because 616 ALREADY exists and it's clearly not the MCU.
I have one on the Marvel side, but I don't think I can post it without getting into trouble. It rhymes with "Duck Face."