My interpretation of the whole thing:
1) Disney wants to disassociate themselves completely from Song of the South, a mediocre film that has aged so poorly into realms of jaw-dropping offensiveness that it has become Disney’s social media PR kryptonite. They are locking it, and any references to it, away in their lead-lined vault and will henceforth pretend it never existed.
2) Of all their IPs on hand, The Princess and the Frog was the one that checked the most boxes toward being a perfect candidate for their flume ride retheme: New Orleans, a diverse and appealing cast of characters, swamps, water travel, singing animals, magic, catchy tunes and a general atmosphere of joy, celebration and optimism.
3) This is today’s bloated Walt Disney Company handling this, so it is absolutely no surprise that they have taken what seemed to be an opportunity for a logical, straightforward installation of the perfect new IP and disappointed fans by implying they removed all the cool, scary elements of TpatF and introduced new backstory edutainment details I’m certain someone in a committee thought would be well-received and awesome.
4) And now we wait and hope they make it work.