The only one with monster masks is the slipknot song wait and bleed, it's not really an emo song, emo is nowhere near that upbeat...
And I know that slipknot do some rather immorral things, but everyone does some bad things, whoever I listen to there's going to be t least something bad that's been done by them, so why not slipknot? I think I prefer underoath though (the first song on the list), see if you can work out what the songs about.