Time to overanalyse the #BowsersFury trailer! :D
(This is a thread!)
To start off, the giant Super Bell has cat accessories that neither existing variant of the bell has. Funny. It also makes a meow, unlike the regular Bells.
Semi-open world? Guess this adventure is very much like 64 or Odyssey.
The Goombas are a different colour to the Cat Goombas in the regular game. Likely because they act like regular Goombas, and so are "cat Goombas" rather than Goombas with the Super Bell transformation.
Junior has his Paintbrush from Sunshine, which is cool. But it has a Junior emblem, just like in official promo art for Super Nintendo World!