If you want another location apart from Haunted Castle, you can also try out Bone-farming at the Haunted Shipwreck Sea Event since enemies can also drop Bones there. For the Haunted Shipwreck event to spawn for you, you will need to sail a Boat in Sea Danger Level 6. ...
either move them to your party or the box, and put them right back in. Doing this allows your Pal’s location to reset to the Palbox, where they usually spawn at the beginning of every session with your base