I Saved the Party and All I Got Were These Lousy Hats

Edit: As this is the top comment, for visibility purposes I'll try to keep it updated every day until we finish this achievement, because Wowhead is so slow to add stuff. Just FYI, new quests become available every day at 4PM Central European Time.

Edit2: I've maxed out post length. The whole reason why I made these comments was because there was no information on how to do these quests before Wowhead was updated. Now there are guides, so there's no reason for me to keep older information in these comments. I'll just keep it updated with the latest content that's not on Wowhead yet and provide links to guides for older content.

Here we go:

All the storylines for I Saved the Party and All I Got Were These Lousy Hats

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2. 
   Chapter 1
   
   1. 
      
   2. Tutorial -> Thoughtful Pursuits -> Day 1 guide
   3. 
      
   4. The Great Detective -> The "Great" Detective -> Day 2 guide
   5. 
      
   6. Tracking Quest -> The Trail's Gone Cold -> Day 3 guide
   7. 
      
   8. Stop the Difference -> Spot the Difference -> Day 4 guide
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3. 
   
4. 
   Chapter 2
   
   1. 
      
   2. Toy Trouble -> Operation Toy Rescue -> Day 7 guide
   3. 
      
   4. The Final Toy -> The Toy Thief -> Day 8 guide
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5. 
   
6. 
   Chapter 3
   
   1. 
      
   2. A Pirate Predicament -> Pirate Foods and Superstitions -> Day 12 guide
   3. 
      
   4. A Pirate Missive -> Pirate Gastronomy -> Day 13 guide
   5. 
      
   
   
7. 
   
8. 
   Chapter 4
   
   1. 
      
   2. Buried Tweasure -> Buried Tweasure -> Day 17 guide
   3. 
      
   4. Festive Reflections -> A Surprising Investigation -> Day 18 guide
   5. 
      
   
   
9. 
   

Credit: WoW Secret Finding & Collections Discord server, channel #guest-relations-secrets

Per Blizzard this event will not start until October 28th Article Link

"Often a thankless job, guest relations has a new volunteer, Alyx, stepping into the role with the lofty hopes of doing a better job than their predecessor. As visitors pour into the celebration, Alyx is under pressure and could use a little help making it an event to remember. Thankfully, they have found a secret-sleuthing tuskarr family who have become the perfect helpers in getting players up to speed with the tools of the secrets trade.

Assist Alyx each week with resolving new guest mysteries by using your new secret-finding skills, and be on the lookout for stolen celebration goods. Follow the rumors and solve the mystery— if you can. We’re counting on you, secret finders.

Players can begin working on the initial secrets beginning on October 28 with additional secrets opening up on November 4."

Go back to [npc=226683] after you are done with the first quest. She may not have the quest mark, but talk to her for a harder task which she puts on the bulletin board next to her. Then grab the [item=228694] from the bulletin board.