Has it ever been explained how Aeris and Leo are related to each other? Are they siblings? Roommates? Cousins? Boyfriend/Girlfriend? Or is it left deliberately vague?
With all of the ship teasing over the course of the series, and that they apparently met for the first time in school where Aeris seemingly developed a crush on Leo, they probably aren't related. (Of course Solid Snake was bullying her, so any canon that strip represented is up for debate.)