Due no absolutely no demand, the sequel noone asked for!
Here is a little guide on how to find all the Witches on the Undead Kingdom side of things. Enjoy!
SPOILER ALERT!!!
First Witch Location
This one is pretty easy, she is just sitting between the quarry and the abomination building in the forest.
Second Witch Location
This (not so sneaky) witch is chilling behind a gravestone near the frostmage.
Third Witch Location
For this little Witch hiding spot we need to start the Voyage and wait a few days until it reaches the Lake of souls area. Shes pretty easy to spot then. 
Fourth Witch Location
This witch can be found near the Wizardtower just above the Marksman.
Fifth Witch Location
This witch can be found near the hospital, just below the weird eyeball dude that calls himself a scientist.
Sixth Witch Location
Alright, now we start getting a bit into the territory where we have quite the high glory requirements to be able to spot here. But once we unlocked this road she is sitting right next to the Templar, just below the Headless Horseman building.
Seventh Witch Location
The last witch is just next to her house… (her hut is just a bit to the left here) the biggest problem here is basically the glory requirement again.