Here's my armchair Imagineering for "Tiana's Bayou Adventure." Put it next to the Haunted Mansion, part of Liberty Square but further up the banks of the Rivers of America (the waterfront part of the current HM queue would be converted to a general walkway, and a new queue for HM would need to be put in, or a boardwalk added similar to what you see in Frontierland). The themeing fits in with the vibe of that north end of LS, and it fits perfectly with the Mississippi vibe, as New Orleans is the mouth of the Mississippi.
Trackless technology. Think Pooh's Honey Hunt or Ratatouille. Round 'leaf' cars with two rows of seats, like your standard dark ride. Four to five cars at a time go through the attraction.
First room is a smaller 'holding' room (cars don't move) with jazz music playing, the sun setting over New Orleans. The door opens and we are in the bayou, drifting between tall trees in this medium-sized room while Tiana and Naveen sing with Louis about being human again as the sun continues to set. The doors open on the other end and the cars stop in another 'holding' room where the sun finishes setting and Ray's family begins to fill the room with their song and light. The lights lead the way into the next room, a long hallway where the song continues and the lights weave their way to the next room. Uh oh! The voodoo shadows capture Naveen in the third 'holding' room, which then spills out into a bayou battleground! Our cars zoom into the attraction's largest room. A variation of "Friends on the Other Side" plays as Facilier holds court in the dark swamps. The 'shadows' fly around the room. Points of interest the car might visit include Facilier offering his hand to us to shake, the masks chanting from a small shrine Facilier has built in the swamp, a Louis animatronic nervously playing trumpet to ward off the spirits, an effect where a shadow seems to 'infect' one of the people in the car. When all seems lost, Ray's family comes and shines light in the room, helped by Mama Odie! The shadows are defeated and our cars are ushered out of the room, now bathed in light, to Mama Odie's sunlit house. In this hallway, the colored bottles throw beautiful multi-colored lights onto every surface as Mama tells us we need to dig a little deeper to find that we've got what we need already! In the final small room, Mama Odie weds Tiana and Naveen as the sun rises over the bayou, turning them human again. The sun is indeed rising, but not so much that we can't still see two bright stars twinkling down on us as we go through the last set of doors in our cars which lead us to the unloading dock.