Asphodel wrote: One thing no one can deny: those green eyes are a big part of the plot. Also, how do you know Lily is muggle-born? J.K.R never specified.
I very much can deny it, actually. Harry and Lily's are not a big part of the plot in any of the books. It's just passing knowledge that gets commented on occasionally, because it's interesting.
And "How do we know Lily is muggle-born?"... Petunia would've surely mentioned something about adoption as another way to insult her sister. Plus we know she grew up muggle before she got her letter.
And Snape calls her a filthy little mudblood in his memory, or something similar. Of course, now you just may argue that he didn't know, and she may have been lying... but come on.
The only way that would be possible was if she was a Gaunt by blood. And... don't see that happening.
Nice idea though, if JKR could make it fit... I suppose it could work. I wouldn't think of the Slytherin colour as emerald green though, more of a... not emerald one.