The snippets of music I've heard so far for Kirby's Epic Yarn have been brilliant, and like many aspects of this game, not really that reminiscent of other Kirby games. Don't get me wrong, I generally like Kirby music but traditionally, the instrumentation is mostly the same and all the melodies are going for that playful, whimsical vibe. In the little I've heard, Epic Yarn is already displaying more variety in that respect. A lot like Wario Land on the Wii, which is known well for its diverse soundtrack.
I assume it's Minako Hamano again - great composer by the way - who seems to branch into types of music that aren't commonly used in games. In fact, go watch the video of the Firetruck transformation, listen to that music and then search for 'Gurgle Gulch' in the Wario Land: Shake It soundtrack. Notice the similarities? Both awesome bass-heavy piano pieces.