NBC has been in NYC trying to cast the TV sitcom spinoff for "Baby Boom" and comes to L.A. this week to look possible actors. No, the role of J.C. Wiatt, played in the film by Diane Keaton, isn't cast yet. . . . We've been seeing a lot of Disney's star executives in the national magazines these days--and Time magazine's is preparing another (ETA early March) on the company's resurgence. . . . Shooting starts in April on "Beverly Hills Brats," starring Terry Moore as Mom to a Bev Hills brat who befriends a lovable burglar (played by Burt Young). Moore also produces with Jerry Rivers and the pair say they have $30 million to spend on six movies over the next two years.