I've been thinking this morning... Basically this is what I would do if I where to change it to a Pixar Land:
-Keep TSMM with the facade that it looks like the concept art has
-Can keep same ride concept that Aliens has (the MJJ thing), but theme it to Bugs Life. I think Bugs Life would be a clever fit for it, you can be sitting in little cardboard boxes (like in Flicks Flyers) while being pulled along by some contraption Flick designed (similar in style to the thing he built in the beginning of the movie for getting seeds). The little bug scouts or whatever they're called can be steering it's
-Some sort of Up boat ride with a giant Paradise Falls forced perspective facade in the distance. The story can be taking place after the movie, and Russel wants to get some sort of wilderness explorer badge. So, you enter the queue through the blimp, and the preshow can be Living Seas esque taking you on a blimp ride to Paradise Falls. Maybe throw in a mild drop in there, but nothing too intense (like Frozenstrom).
-The Monsters Inc door coaster (a must!). This can be a phase two thing, with the goal to get the flat ride and boat dark ride open first for capacity. This would be the main e-ticket of the land though once opened. A full elaborate queue going through the main lobby, the many halls, the trash compactor, the area with the scream extractor, even the locker room for fun Monster gags in the lockers and a creepy Randal animatronic. The ride part can be both intense and have show scenes (I could do a full elaborate write up but I think this is enough
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-Replace that main food area with a Pixar Studios esque brick building. Include a cafe style restaurant, merch, meet and greets, and a One Mans Dream style exhibit for Pixar.