All Ghosts Locations
After you reach the Last Resort, you'll be able to access the haunted pool on the right side, outside of the ship. In there a Top Hat Ghost will ask you to give out Spooky Maps to the following ghosts.
1. Sunhat ghost is in Otherworld. After going right from the main area with houses and such, keep going until you reach the area with the Wormhole. From there you gotta go down, and battle a Venus Flytrap. There will be a wooden bridge leading to the right. There, you'll see MARI with her picnic blanket. The sunhat is on her right.
2. Glasses ghost will also be in Otherworld, but in the junkyard's conveyor belt section. It's sitting on a sofa in a room with a bookshelf, located above the Life Jam Guy.
3. Propeller ghost is in the right side of the Vast Forest. After going right, try to go NorthEast till you see a long ladder. Climb the ladder and go up on the right side.
4. Beard ghost is in the Orange Island. It's on the rightmost side of the main area, near the joke board and the guy that makes face prints on the walls.
5. Crown ghost is in Sweetheart's castle. It's in the gallery, which is accessible by going through the bottom left path and going past four sprout moles that walk up and down to hinder you.
6. Mustache ghost is in the Last Resort, on the fourth floor. There are two rooms there and it's the right one that you have to go into.
Afterwards, go back down to the haunted pool.