I absolutely love the ghosts! They are proper spooky!

The raven gives me a little trouble, because he's generally symmetric, but off-center itself. If his direction or his target felt a bit more diagonal, it would already help, pulling the whole gorgeous picture together. His eyes appear to have beams, but those beams feel like a problem with the paper or an eraser accident of sorts. I would have left those out. I love the glowing eyes, though, they're fantastic!
I know how hard it is to paint birds, especially while in flight, but it could be kick ass to have the raven in a more dramatic asymmetrical pose, like shortly before taking a dive or so.
The shading of black feathers or black anything, really, is really challenging. I think, you've given it a good go already. I could imagine a more defined highlight might help? On the other hand, studying crows in the dark (

) may help. Maybe indoors, like some stuffed versions? It's a fantastic challenge that, again, makes me want to resume the "Sketch Topics" thread!
Maybe something like "Black feathers" or so... could still be very liberally interpreted.

All in all, though, SUPER mean scenery in brilliantly moody light that still manages to reveal enough to arrive at this elegant tribute!

(The city scape in your modified versions is nice, too! Just the "Nevermore", eh...not necessary at all. Please, don't put me on "fonts" just yet!

)