I'm more comfortable using IPs if they're used as a sort of primer to a country's culture or history. If the Canada pavilion wanted to update their film to include the moose from Brother Bear, but used them as a way to talk about Canadian history or actual Canadian folklore or legends, it would be an entertaining way to do it...it would also be ironic because the moose are based on the Bob & Doug MacKenzie characters Dave Thomas and Rick Moranis created for SCTV, and they were created specifically as a rebuttal to criticism from the CBC that, by satirizing so much American culture, the show wasn't "Canadian" enough. The reaction was along the lines "most of the cast and production crew are Canadian and we shoot in Canada. What else do we need to do to make it Canadian - have two guys wearing toques and drinking beer in front of a giant map of Canada?" And boom, legends are born.
But back on topic, if Remy from Ratatouille was used as a conduit to talk about French culture or history, I wouldn't find that to be a bad thing (and anything that gives Patton Oswalt a smidge more work, I'm down with it, poor guy). If Mulan did a brief history of China, great, if it were real history (which is a bone of contention with the Frozen Ever After attraction). And use IPs in Future World much the same way, like the Nemo overlay in Living Seas, if it satisfies the original plan to educate AND entertain, even if the delivery method is not what WD himself preferred.