I think it's really Iron Maiden. Bendis, as is typical of him, must have chosen the character by name alone, not bothering to do any research on her.
Many thanks. It is probably meant to be a private joke, since Riri's alias is Ironheart and not Iron Maiden.
Indeed, you're right. Normally, it should be unlikely that Stark Enterprises publicly hires the Russian Iron Maiden since she is a former foreign spy & assassin.
(well, except if my speculation becomes correct : the Mandarin has secretly taken control of Stark Enterprises through Amanda & Arno.)