I find it very hard to believe that if Disney pays some sort of agency for the use of the music, that it's taken them this long to determine HDD is live theater.
It's not the agency (ASCAP, BMI, etc.) that cares, it's the individual copyright holder who cares, because the money they'd get from ASCAP/BMI is nothing compared to the money they ought to be getting for live show usage. In a case like this, the individual copyright owner is only likely to know about things they stumble over, or someone tells them about. So yes, 37 years could go by before someone in an office in NY learns a song he/she is administering is being used in a single show in the middle of the "Wilderness." If a song plays in the forest, the sound may not carry all the way to NY. There are computer programs that scour the electronic media for mention/use of songs (and people, companies, etc.). Live performance can't be monitored so easily.
Changes at Disney of this relatively small nature? Disney wouldn't, and rarely has, said a word. It's always been up to the rumor mill. When a new version of a show is in the works, someone sees the casting call posted. Maybe a CM rehearsing a new version of the show gets the word out, or a CM has heard that a show is going to be changed.
We happen to thirst for info about every little thing, but in the big scheme of things, it doesn't mean Disney has any obligation to feed that curiosity. The Disney Parks Blog is the best thing that's happened for folks like us, period. Before that, only changes that were of interest to the general media (likely to get space in newspapers or on TV) were announced. Even the Orlando Sentinel isn't likely to give the change to part of a show a mention. A change of this sort is below even the Disney Parks Blog's radar. It's not something the producers of the show would care to publicize, unless it was about a new song by Alan Menken or the Sherman Brothers, so they're not going to get word of it over to the bloggers.
So, maybe two songs are being changed in the HDDR. Maybe the reason they're changing has to do with copyrights/royalty payments. Will that matter to anyone but the CMs who perform the show, and fans who know and love the show just as it is and consider it some sort of Disney historical legacy that must be preserved?
To this day, around 13 years after the fact, There are still publicists who cringe if you mention the words, "Mr. Toad's Wild Ride." The publicity surrounding the closure
in 1998 was so traumatic for Disney that I'd bet that, when they were planning to announce the closing of the Pleasure Island clubs (especially the Adventurers Club), they had strategy sessions titled, "How do we prevent a 'Mr. Toad' from happening this time?" Ever since Mr. Toad, their policy is to say nothing, or next to nothing, about a change until the attraction has been shuttered, and the construction fencing put up (how far into the construction process was it before they admitted they were building Bay Lake Tower?). There are exceptions, of course, like the Fantasyland Expansion and the Pleasure Island closings, but those were a little too large to keep out of the rumor mill (tell that many entertainment CMs that their contracts aren't going to be renewed, and there's little chance of it staying quiet). Their line of thinking is, "If we won't benefit from early publicity for this change, say nothing."