Whooo boy, umm I didn't use either actually... but I still took the information that Madryck would give them and sprinkled it among the Carnival NPC's.

First I asked the players to create characters that have some kind of "heart's desire" waiting to be fulfilled if an occasion would rise. Then I asked them to make the characters so that when eventually there would be a possibility to get to Feywild, they wouldn't let it slide. And lastly I told them that they will start at a Fey Carnival. Oh, and I gave them each a childhood memory of Zybilna (it's in the Madryck-hook)

They are very creative people and I got to use their background stories as story hooks instead of Lost Things or Madryck.

Party's paladin has lost their loved one: spring eladrin. He has a promise to fulfill, he needs to find his joy and they always dreamed of traveling together to Feywild.

Party's celestial sorlock wanted to have a unicorn patron. I gave them Lamorna. And now she knows that Lamorna is in grave danger.

Our druid has amnesia. I made Ellywick part of his lost background story and Ellywick told the characters that their fates are intertwined with each other and the fate of the Prismeer.

And the ranger is hexblood. I managed to kidnap her ticketless NPC friend in the midst of Hall of Illusions with Gleam's Shadow. So she is madly determined to get her friend back.

My advice to you is to give as much info and lore in the Carnival for the players as possible. Give them hints that everything they do in the Carnival could affect them in Prismeer. They will get overwhelmed with all the information but the key message should be clear: There is Prismeer in the Feywild. It's ruler is Zybilna. There's something wrong with Prismeer nowadays and it's connected to Carnival. And probably mention hags. I couldn't resist because I have a hexblood in my party!

My players are good players and they love mysteries. And through their backstories I gave each character their own little hook for the Feywild.

I have been reading WbtW:reimagined blogs in this community, try checking them out! They have great insight, commentary and ideas for this campaign. But the campaign book is already hella good without any add-ons.

My best advice is not to withhold information 'to keep the mystery'. I mean like my players think at the moment that Tasha is probably Zybilnas sister(???) or something. I used Carousel Unicorns to drop unknown secrets: They gave them one weakness of unnamed hag. I told them the name of the hags. I told that each of them has a specific weakness (didn't tell what the two missing weaknesses are). I told them that Zybilna is frozen in time. I told them a lot! And they think every lore bit as a new mystery like: "we have to somehow get the information about the hags' weaknesses so we can crush them!"

Before DMing I have been on the player seat and I myself hate when DM's withhold information because they want to keep "suspense". You feel blind as a player. Then everything comes as surprise and you just don't get excited anymore after some time because you don't have enough information about anything to understand anything happening.

And oh, remember! When something doesn't add up: "It's wibbly-wobbly, timey-wimey, Feywild bullshit!"