Stacking

Credit to iamcloud for Text
Credit to RoosterTeeth for Video

(For Reference I will use the the "Seaside Safari" as North)

1. Kodiak Bear - Use a pelican to fly to the nest on the wall of the ship by the Seaside Safari, drop into the room and the Kodiak Bear is in the room (Found near Seaside Safari after that)
2. Pied Piper - On the first level of the ship on the east side, there is the Pied Piper on a platform if you play a violin he will come down and you can stack into him
3. Hans Allendorf - Found on second level near the stairs going up on the east side
4. Mummy - In the Argyle Ballroom on the left hand wall when you enter
5. Ronaldo - Found outside the Argyle Ballroom (not sure of the exact location a little foggy on this one)
6. Peatrice - Found in the first hallway south of the Seaside Safari one in the middle turn south and the room on the right is where she is at
7. Gwendola - Just outside the "Artistic Makeover" shop (North hallway of the second level, on the north hand wall is a door into a room with a room on both sides he is in the room on the left)
8. Prestige - Found on the second level of the ship on the south side (Dog with a shirt on)
9. Caviar Chef Vladimir - Found through the small door on the left hand side of the south wall in the buffet area
10. Gruel Chef Hornsby - Found around the buffet
11. Buffet Host Yves - Found in the buffet area, doorway just south of the upward stairs on the east side of the ship, standing at the podium
12. Mess Officer Morris - Found on the third level just at the top of the stairs
13. Ferdinand Reginald - Once you complete all 5 ways to "Sabotage the Exhibit" he will be standing in front of the Argyle Ballroom
14. Exhibit Guard Walter - Found in the Argyle Ballroom on the left hand side in front of the mummy
15. Gilded Sarcophagus - In the Argyle Ballroom on the left hand side of the stage
16. Madame Habitant - Once you get the 4 people to go to the Captain to complain you will have to stack into all of them to complete the level
17. The Hunter Darby - Once you get the 4 people to go to the Captain to complain you will have to stack into all of them to complete the level
18. Professor Ramses - Once you get the 4 people to go to the Captain to complain you will have to stack into all of them to complete the level
19. Doktor Exakt - Once you get the 4 people to go to the Captain to complain you will have to stack into all of them to complete the level
20. Map Assistant Gilbert - Once you use all 4 methods to "Muddle the Maps" he will be in the doorway to the Towel Service / Map Room
21. Pirate Chuck - Found near the Argyle Ballroom
22. Captain Swing - Found after beating the level, near the exit of the ship
23. Safety Inspector Ludd - Found at the Seaside Safari you can stack into after using all 4 methods to "Cause Chaos at the Safari"
24. Field Commander Appleyard - On the Cannon at the Seaside Safari
25. Bobby Webb - Found outside the club "The Buried Treasure" after finishing the level(Washboard Player)
26. Billy Webb - Found outside the club "The Buried Treasure" after finishing the level(Jug Player)
27. Dropped Anchor Drew - He is found in north hallway of the second level, on the north hand wall is a door into a room with a room on both sides he is in the room on the right

Note - The Illusion Family can be found near the Argyle Ballroom after you stack them together
Note - Captain Swing, Madame Habitant, The Hunter Darby, Professor Ramses, and Doktor Exact can be found at the exit to the level once you have finished the level

All credit to Rooster teeth. I think a little bit of visual help will go down very well with Kennansoft guide, and its quite a funny video as well.