Little tardy to the party but this answers the question. What he uses to throw are a magicians gimmic called "Throw Streamers" It is long lines of paper wrapped up and when thrown spread out. You can see them in the video link. Hope this helped.
That would depend on the intended use. Silly string plus an ignition source is a bad thing. Is anyone coming in contact with this stuff allergic to it, or might there be adverse reactions of some sort? Ever try to clean that stuff up? I almost prefer to sweep mylar confetti off of marley.
My experience is that this stuff is best used outdoors for block parties. I'm not saying beverages are involved...I"m not saying they aren't.