Oooh, I've been hoping for a speculation thread! I have quite a few ideas. I won't take into account anything from the surveys, although those did have some interesting concepts... also, sorry if I'm getting carried away in my theorizing.
Super Nintendo World: I think it's time for Super Nintendo World to move past just bringing in Yoshi, and I have two theories; one that is boring, but practical, and one that is more exciting but less likely.
- Donkey Kong Meet & Greet - The easy option. Bring over the costume from Orlando, as well as some of the merchandise and food options. Beyond the fact that reusing stuff from Orlando would be a bit boring, I could also see there being capacity issues if all the area has is a singular meet-and-greet as opposed to the multiple that the Yoshi experiences had. You could potentially mitigate this by introducing a Diddy Kong meet-and-greet, but I have doubts that they'd do so.
OR
- Super Nintendo World: Wonder Flower Takeover - The exciting option. Introduce Daisy and Bowser Jr. meet-and-greets using the parade and event-exclusive costumes from Osaka, plus a couple of the Yoshi colors to round things out. Add some new lighting effects and music to change the feel of the land, introduce some new merchandise and food options, and boom, you have a completely refreshed Super Nintendo World for Fan Fest.
The Wizarding World of Harry Potter: I have very little love for this IP anymore, so I just kinda threw together a concept, sorry y'all.
- Yule Ball Celebration: Hogsmeade is decked out like it's open Hogwarts Prom. Special music, lighting, and performers decorate the land, and they offer unique food and merch as usual.
WaterWorld and DreamWorks Theater: We have a couple pretty obvious choices for these!
- One Piece: New Pirate Show - The Grand Pirate Show again, but remixed. Bring in some different antagonists, perhaps add Robin and Franky to the lineup, and add or change the order of the stunts. Keep the momentum going from 2026's stellar show without risking a drop-off in interest by copy and pasting it. The Grand Pirate Encounter would return as well, of course, perhaps also adding Robin or a Chopper costume character to meet.
- Godzilla vs. Evangelion - You could pick any USJ 4D show, but I think getting a 2-in-1 of popular Japanese IPs with huge fandoms gives the Godzilla vs. Evangelion show an edge over the others. I do have a theory that the dedicated Godzilla show from USJ is going to be the DreamWorks Theater attraction at HHN this year, so if that happens and they want to to do a different IP for HHN, you could instead do the dedicated Evangelion show or something different entirely like JoJo or Attack on Titan. There's no wrong answers for what to bring from USJ, honestly.
Tram Attraction and Walk-throughs:
- KPop Demon Hunters: Backstage Pass - The tram attraction! Assuming the popularity keeps up for the IP, you're gonna need something high-capacity, so you could have everyone board a tram to the backstage of a "music festival," AKA, the plot where they usually drop you off for the Terror Tram. Once there, you can watch a short live show where Huntrix performs, the Saja Boys perform, and then they battle each other, and then you can move on to the "backstage" area where you can meet the Rumi, Mira, Zoey, and Jinu as if you're at the backstage of a concert. Preferably, you could have the meet-ups behind a curtain so that there could be multiple actors for capacity purposes.
- Spy X Family: Operation Extraction - With how big anime has been at the event, I could see them finally doing a unique anime attraction that isn't inspired by USJ. For those purposes, Spy X Family is easily the most practical Shonen Jump IP for a walk-through, as there's no supernatural abilities and it's mostly based in realistic locations. Have an adventure where you follow Loid on a mission, run into Yor along the way, and Anya is there for cute shenanigans. Outside you could have Loid and Yor meeting guests too.
- Teenage Mutant Ninja Turtles - This could theoretically work as the tram IP in the New York sets, but I like the idea of KPDH too much, and I think a walk-through in some sewers with the Ninja Turtles, Splinter, April, and Shredder could be really fun. I don't know much about this IP, so I don't know the exact details of what they could do, but considering Paramount already collaborated with Universal for Star Trek, I think TMNT would be another good choice for a nostalgic-but-still-popular IP from them.
Misc.: Just wanna mention that I don't expect BTTF, Jurassic, or Jaws. BTTF could very well be getting an attraction soon if it's the Supercharged replacement, Jurassic was already a last-minute low-budget addition this year, and Jaws is heavily represented in the summer events each year. I'd love to be wrong about BTTF in particular, but it's not what I expect.
- E.T.: The Return - For the most part, this could be a simpler, lower-budget affair akin to the Jurassic World exhibit, feat. photo ops of iconic moments, a stand with themed food, and actors playing the human characters. They could even put it in the exact same spot as the Jurassic exhibit, as that's right by where the attraction used to be. The higher-budget "draw" to this zone could be an E.T. animatronic meet-and-greet. If they can make massive animatronic puppets like the Hippogriff or Beholder just for some limited-time walk-throughs, I think they could make a simplified E.T. animatronic to talk to and get pictures with.
TL;DR - The lineup of IPs that you'd see on the merch is KPop Demon Hunters, One Piece, Spy X Family, Ninja Turtles, E.T., the HP cast in Yule Ball garb, Godzilla and/or Evangelion, and Donkey Kong and/or Daisy. Probably an overly generous lineup but speculation posts are for fun anyway!