Oh, I didn't see that.Actually, I think the "Maniac Dance demo" won't feature any vocals at all.
Just look at the description - (M: Timo Tolkki)
M stands for Music.. the L on the other songs' descriptions, on the other hand, goes for Lyrics.
Since no one was given credit for the lyrics on the demo, I guess there are no lyrics to be
given credit for, and hence, no singing, or any singer at all for that part.
Well, that should answer the question as to whether Miss K. is on the demo version or not!