Dawn doesn't do much wax stripping anyhow, and it sure doesn't dent Collinite for me.
Paint cleaners cut right through it though, Meg's Deep Crystal Step #1, AIO, SRP, stuff like that'll do it. Or you could use rubbing alcohol. Or you could just let the abrasive (that you'll probably need after winter anyhow) cut through it, which is what I usually do.
I like #16, but for the winter I put some 476S over top of it (wife's car, she uses it for long trips). Come spring I just use a mild polish and go back to #16.
I wouldn't worry too much about pre/post VOC versions of IW. I've yet to hear of any issues with the newest version. But then I'm the guy who bought a case of 476S before the change just to be on the safe side