Ororo has been featured in more video games than either of those characters, has never been killed for any extended period of time (you can say the same for those characters with the exception of kitty and beast), has been featured in every major xmen cartoon and even in some non-men cartoons (none of those characters you mentioned have), had/has a theme park ride dedicated to her (none of those characters have), and within the comic world has ties to multiple teams including fantastic four and the avengers. Again, when considering all the categories they mentioned I think I sound case can be made as to why she would be number 2.