Essentially this. It's more likely to be Toadwood Forest as it goes multi-grouped games first and then single entries if I remember correctly.It flat out lists Britney Spears as a potential candidate.
It's not a serious article.
The idea of the track being "Beware the Forest Mushrooms" is so widespread that it's popular belief. People have been saying it since 2008, and the fact that the track was far more likely to be "Toadwood Forest" from Mario & Luigi: Partners in Time is seldom mentioned.
The dozens of people who've uploaded that remix on Youtube only served to complicate things. None of the removed tracks are present in the game anymore, other than a name and an empty file. That remix is 100% fake, as are any other supposedly unused tracks uploaded to Youtube that are claimed to have been ripped from the game.
Hmm...I'm surprised no one has guessed the theme. Guess you guys are bored of the theme game.