Soooooo.... it seems that Happily Ever After isn't exactly coming back. I just randomly watched a video of all of the announcements and non-announcements and here's exactly what Josh D'amaro said:
"next year, we're going to bring back the Happily Ever After anthem".
It seems like what's going to happen here is that after the 50th celebration is done at the end of March, they are going to switch over to a show 100th anniversary show that will use the Happily Ever After song. I'd expect it to be called something like "Happily Ever After: 100 Years of Dreams". I'd expect the contents of the show to be fairly different from original HEA to celebrate 100 years and then possibly just move on to a different show again after the 100th is over.