I am probably spending way too much time thinking about this.
I've been writing Remus-and-Sirius conversation snatches. And other-people-about-Remus snatches. And one where the person who *suggested* it might be Remus (Order member, not Peter, though Peter encouraged it) apologizes to Remus. (I sketched that one. In class. Then I had to explain to seatmate that I was doing Harry Potter fanart and he laughed at me. :P) It's all very fanverse. And fun.
Except I suddenly have overwhelming urge to read/see the scene of James, Lily and Sirius (possibly with Peter present) sitting around a table, probably over booze, and agreeing Remus must be the traitor.
Unless there was just unspoken agreement. I guess that would be worse.
But I still want to see it/read it. I'd write it, but I can't quite yet envision it clearly enough.