Well, we still have one victim to guess and since it's the victim of the very first murder it can't be Katniss Everdene (the only other theoretically remaining option), since she was expressly excluded in the game's first round.

Walter Mosley's Red Death, which I finished a few days ago, is genre crime fiction; in addition, its author's first name begins with one of the letters in WATSON.

Lydia Bennet can't possibly die too many literary deaths, so I kind of hope she's a victim in our round as well.  (Mean streak -- me?)

Margaret Drabble's The Red Queen contains an extremely annoying POV character in its second part -- who also happens to do more than her fair share of stupid things -- in addition to which, the author's last name begins with one of the letters in "Lydia".

Since Agatha Christie has recently been observed visiting Scotland Yard (and we know she's not the suspect), I think it just might be possible she's been asked to identify one of the victims as Mrs. Oliver.  Of course, the identification might have come out as a negative, but then again ... it might not. 

So I'm going with this as a victim guess, with Ms. Christie's own One, Two, Buckle My Shoe, which I just finished listening to, and which happily fulfills all three tasks of this particular card.

The Bloody Chamber is a short story collection, which reimagines fairy tales. So this book fits the task for a book that is set in an imaginary place.

To paraphrase the Red Queen: "Off with his head". This is for Hermiones teeth! (As you can tell, at the moment I´m not a big Snape fan).

This book fits all the required tasks. It published after 1990, the last name of the author starts with an E and the female main character of this novel is a morally ambiguous character. As a matter of fact, I liked her a lot.