Everybody is not gay. The story is about Harry, from his point of view. The people closest to him happen to be gay. If I was writing about everybody in the wizarding world, they would obviously not all be gay, but I'm writing about these particular characters... who happen to be gay. Everyone being straight, as in canon, is just as unlikely. Right now, three people (one of whom is dead) are gay. Hardly everybody.

Snape can be bisexual. If Harry was inclined to give it some thought, he would probably come to that conclusion, given that he knows Snape may have a son out there. But I don't think Harry is going to sit around pondering Snape's sexuality beyond what is right in front of his nose, which is Lupin/Snape.

I'm glad you're enjoying the story despite not liking the slash... I think that's just not something that's very easy to agree on, just like pairings are not easy to agree on (regardless of if they're het or slash).

That's why it's AU. Snape can be straight in someone else's story. :-)

I was planning to put in a Harry-finds-out-about-Sirius/Lupin scene, but it didn't fit anywhere. So the premise is that he knew, or suspected. Which doesn't man anyone else knows or suspects. I might still do something with it, so it isn't left hanging, if it fits in anywhere. Possibly when others find out that Snape and Lupin are pursuing a relationship.