A fun thing to do with the witch is to, on first encounter, disguise her as one of the townsfolk who's drowning. The freeze+grapple while underwater usually results in a dead PC and a big "oh shit" moment.
Great review! Thanks for doing it. I plan to have this as part of my LotFP Adventure Campaign as the penultimate adventure before they go into the Veins of the Earth.
Great adventure! I've run this for my main group and they loved it. Hope to run this again for the group I play with at a local shop, going to wait for the release of demon bone sarcophagus first though.