I've said this before about the music rule, but I think it bears repeating:
The purpose of the "music rule", such as it is, seems to be not having songs of the same series show up relatively recently after a song of that series was already revealed.
Thus, I posit that it would not be unreasonable for a song to be revealed a long long time after that series already got a song.
Example: The Legend of Zelda already got a song, but it was 3 months ago, so it getting another song would not result in two Zelda songs relatively close to one another. By contrast, we probably won't see another Fire Emblem song soon because the last one was revealed much more recently in comparison.
I have no evidence to back this up other than my gut.
I think this is really possible.
Music theory could still apply somehow even with a Zelda exception. Zelda's music choice was up around E3, I think if we get one now it would be fine.