Here Ghost Nothing by Elle Adams

Maura's life-and her brother's afterlife-is on the line.
Trying to stop an enemy that always seems to be one step ahead of her is a challenging enough task without also having to contend with the ghosts of her past, but the clock is ticking down until Halloween night, and Maura is willing to seek anyone's help to stop Mina Devlin from enacting her revenge against Hawkwood Hollow for thwarting her plans.
Even her former coven.
Can Maura protect both the living and the dead from certain disaster, or has the Reaper Witch's journey come to an end?