I think what would help the Pixar Pier idea be a lot better would be to center it on one IP or setting.
"Pixar" isn't a theme. It's a studio. The movies all take place in wildly different universes and settings and time periods. Marvel or Muppets work as a unifying theme because they are one universe/world. Pixar doesn't.
Obvious answer would be Toy Story Pier. Keep the same aesthetic style of Toy Story Mania. A slight toyified version of a classic California pier. But don't go as garish or tacky as the critter carousel looks. Keep it subtle and classy.
Woody hosts Toy Story Mania. Jessie does host the carousel (but no giant statue and keep it looking like a standard carousel just with critter instead of sea creatures). Buzz hosts Screaming (kept mostly the same just with some LGMs repairing parts of the coaster and the coaster cars given a purple/green color scheme). Wheezy singing jazzy music somewhere. The carousel gets the Pixar Yellow Ball on the face of it. One of the Toy Story Land flat rides placed where the inside out ride is going. Etc.