Aside from that...looks like you've completely missed my point. Your 30 year old sister is hardly the target audience here either, and yet you still figured it was worth mentioning; seems like we're not far off the same wavelength.
I'm confident that no one I know who wasn't at least slightly exposed to comics or Superheroes as cartoons anytime in the last twenty years would be able to recognize even the Fantastic 4 outside of obvious visual association before the movie came out (even then, I'm betting most would've picked them out as 'Rocky-guy' and 'Fire-guy' or 'Torcher' and 'Stretchy-Guy.' The giant number 4 on the chest would certainly help a lot more in naming the group as a whole than GL's lantern shaped chest emblem.) Either way, as I see it there are still far more recognizable individual DC heroes than individual Marvel heroes as far as the general public is concerned. Having had more recent films in theaters helps, but even more DC characters have had better recent exposure right there on basic cable. In fact, I think it's their existence as part of the cultural vernacular in spite of the very lack of there having ever been a solo Green Lantern, or Flash, or Aquaman movie that proves exactly how recognizable they are.