Do you think that the guys at FSG feel more forced to make mashups with actual song lyrics in them? This is not counting the house,techno,trance, etc songs that have the same 1-2 lines of lyrics being repeated over and over again.
 
Is there any confirmation that there will be any tracks in the game with no lyrics?    

I think the vocal track, as warped or distorted as it may be will still stay intact. I mean, who wouldn't want to rap a little "make him ma-make him ma-makim makim makim clap to this"?

I don't know how the vocal parts will play out.  But I wish they had them for the Spooky/Insane in the Brain mix, because I get it stuck in my head so often, singing it would be cathartic.
 
What does the vocal track do when the song has scratching of the vocals?  Just not chart it for the singing player, or chart in some stuttering?