I would love to see Wall-E in The Land...And if working within the earlier half of the movie feels too depressing/not inspirational enough, a "continuation" building off the end of the movie (when the colony returns to Earth and the tree is planted) has the potential to strike a very hopeful note and be educational. Definitely would work well as a replacement for Circle of Life (or as a "guide" through Living w/ the Land). Although TBH, I would imagine Lion King characters are still more recognizable than Wall-E characters for children today.
Wall-E in The Land, BH6 and Inside Out in Future World and maybe Wreck-it-Ralph in Tomorrowland (I guess that's still on the table, pending the sequel's success?) feels like the way to go for me.