The bunnies that appear in the second Marching Orders variant in the remix are actually the Alien Bunnies from the WarioWare series, another series worked on by the developers of the Rhythm Heaven series. This isn't the last time they've appeared in the series, either; they were also used in Marching Orders in Remix 8 of Rhythm Tengoku and other games.
If you add up the numbers that were used to be remixed, you get the number 7, the exact same number as this remix.
In the first variant of Tap Trial used in this remix, the giraffe was replaced by a dragon, but it doesn't appear during the remix. The second variation uses the original giraffe, however it doesn't appear there either.