I think they're just using "Earth's mightiest mutant" as a play on words because it's the Avengers, not because Namor has used it before. It could be...
Laura did not like Kurt in the beginning, lol, can't say I blame her (with Kurt trying to make her mad, though its mostly a tactic) but she did give...
I think Spider-Man once joined the Avengers back in the 80's and it lasted all of like one day if that. It was definitely being shown that he doesn't...