This is an easy deck to play. It leverages 2-for-1 creatures (doomed traveler) or 1/1 spirits, with sac spells (bone splinters, midnight haunting) to trigger morbid for Tragic Slip and Skirsdag High Priest. The Desecration Demon typically gets through too, because sacrificing creatures triggers morbid as well.

For non-budget options, Sorin, Lord of Innistrad is terrific, I'd add 2x and take out the typhoid rats. This plays OK without Isolated Chapels, but they'd obviously be an improvement.

Vampire Nighthawk was a tough one to cut since it is so solid, but with it, the deck had too many 3-drops and Midnight Haunting & Lingering Souls. Other options: Loyal Cathar (if you've got better mana fixing), Demon Lord of Ashmouth (triggers morbid & gives you a large resilient creature).