Yooooo…. What if you’re the reincarnation of Anne-Marie!! That would explain why your ancestors, who certainly had knowledge of the supernatural, could have glimpsed their family line ending with you or something because of René and would have had reason to imprison him beneath the very floorboards he set. Maybe you touching his skeletal hand was the initial catalyst for his revival. Maybe the witch is or has been biding her time for this opportunity to remind him how none of this would have happened had he not turned her down 300 years ago.