Your whole point, originally, was that people wouldn't be able to handle the obscure nobodies that weren't in cartoons and whatever. Well, the point is BS. One only needs to look at Capcom's past Marvel games to see that. There wasn't outrage at Blackheart and Shuma-Gorath, in fact , there was the opposite. There was no outrage that the cast of characters in Children of the Atom wasn't made up mostly of the biggest X-Men characters at that time. Nobody was mad about Jin Saotome, SonSon, Hayato Kanzaki, and Strider Hiryu being put into the Capcom side in those games.
The internet was god damn huge
before '99. It was huge back when basically everyone was using AOL and talking in their many many chat rooms. Video game sites like IGN had already been around for a few years by 1999. Sites like Smashboards were around in '99, they just weren't there for a game released that exact same year...actually, that's not true, No Mutants Allowed has been around since '97. Games that could be played online had huge boards before '99 too.