|Soucouyant Picture from "What's the Idea?"|
You can protect yourself from soucouyants by sprinkling rice in your entry way, because soucouyants have an OCD like trait of having to pick up and count every single grain of rice.
If they are unable to return to their skin before sunrise, then they die. This means if there is enough rice in a doorway, a soucouyant will die if unable to pick up all the grains before sunrise.
While the fireball shape is the most intimidating and frighting form the soucouyant takes, it also is the state in which the creature is most vulnerable. One can kill the soucouyant by sprinkling salt on the soucouyant's empty skin when she is gone hunting for the evening. When she returns to put it on before dawn, she'll explode.
Anyways, this is the kind of thing that gives me tons of imagery to work with in writing a short story. Looking forward to finishing it.
Read more about soucouyants here and here.