THEN One half of the powerhouse Corey duo of the '80s, responsible for such big-screen hits as ''Lost Boys,'' ''License to Drive,'' and ''Dream a Little Dream''
NOW Guest-starring on ''The Guardian'' (Jan. 7) and working on his next album
WHY HE'S IN THE HOUSE Feldman claims he and Scott Baio had an idea for their own live-in reality show a year before ''The Osbournes.'' ''I was a bit ahead of the game on that. Obviously it was on my mind at the time, and it all came to a culmination with a show like this.''