A fun way to look up superheroes? Go to the Superpower Wiki and select a random power. Guarntee someone from either Marvel or DC has it.
Plus we can always say the heroes had more children than just ours. Maybe they split remarried and had another kid who was ten years old during the original Academy RP and couldn't attend yet. Or maybe they are the younger full blooded sibling to one of our existing characters.
I can just see a sibling of Connor's, the complete opposite of Connor himself