i like the first composition (girl with legs dangling over empty grave) and the second (vampire) because they have the most interesting angles. however, in terms of mood, i very much like the girl embracing the tombstone in the last piece. if you could somehow incorporate her into the second drawing (perhaps as the remorseful vampire?) that could result in a rather moving image. try to avoid morbidity and go for a more melancholy mood (which i sense from the other poses is what you are aiming at) i imagine this series as very dreary (grey, blue-grey), mournful, and romantic. thoughtful details like wear on the tombstones, black crows, or naked trees in the distance could add a lot of character, as well. good luck!
Thanks! That's very helpful :)