The Redcaps are brutal and violent fey. Sling bullets shot by redcaps glow blueish-greenish, dealing increased damage. They steep their caps into the blood of their victims and grow more powerful by this practice.
The strange woman is a Lampad, an underworld nymph. They are eternally saddled with sadness, weeping and mourning. Their wails can make someone nearby Shaken as long as their crying can be heard. They have access to druidic magic up to third level spells. They have a special connection to stone (but not earth), able to talk with rock and meld with it when threatened. They have a damage resistance bested by cold iron.
Uncle Skeletons are actually fey, not undead. They share most undead strengths - with the big exception of being susceptible to mind-affecting spells. They are hurt by positive energy and healed by negative energy. While they cannot be turned, they can be held at bay with a forcefully presented good holy symbol. They like to play pranks, but of a rather dark and deadly kind, backed by Bard magic and weird martial maneuvers. Like the skeletons they resemble they have a damage resistance bested by bludgeoning weapons.