ON THE TOWN: You've probably heard that many local clubs have been turning away large numbers of potential customers due to strict city fire-law regulations. One of the nightspots having the most difficulty has been the Club Lingerie, whose official capacity is 205 persons these days. Last weekend, due to a large guest list from Island Records, the Lingerie found itself oversold by 50 tickets for its Julian Cope show. People who arrived with advance tickets after club reached capacity were given a choice of either waiting until someone left or taking a refund. Those who chose latter were given a chit that read: "I got screwed at the Julian Cope show at Club Lingerie. But I got my money back plus $3 and this ticket is good for any one show through Sept. 1, 1987." . . . The Bel-Fires, who are a popular group on the local club scene, played a special show the other night for birthday girl Justine ("Family Ties") Bateman. And guess who sat in, on guitar of course--Michael J. Fox, who, judging from the enthusiastic reaction, hasn't forgotten some of the moves he picked up making "Light of Day." . . . If it sounds like something's missing as you spin your radio dial each night, you're right. April Whitney, who's been a strong ratings force on weeknights at KROQ-FM, has given up her 6 to 10 p.m. slot "to devote more time to her other commitments," which include a co-host stint on the syndicated "Top of the Pops" TV series as well as a budding acting career. Whitney's time slot will be filled by KROQ vet Dusty Street. . . . And talk about a super session! The Grafitti Band featuring Jesse Ed Davis and John Trudell presided over a recent star-studded jam session at the Palomino. Guests on stage included Bob Dylan, George Harrison and John Fogerty, who all contributed to raucous versions of such standards as "Knock on Wood" and "Lucille."