Yoko Ono, Sean Lennon, New York Mayor Ed Koch and several hundred invited guests dedicated Strawberry Fields, a 2.5-acre memorial garden in Central Park, to the late John Lennon yesterday. The garden was not due to open until today, but hundreds of fans were waiting outside the entrance, so park officials took the chain link fence down yesterday . . .

Elizabeth Taylor and Roddy McDowall, longtime friends of Rock Hudson, will be among a group of about 150 friends who will gather at the late actor's Beverly Hills home Oct. 19 to honor his memory, says Chen Sam, Taylor's spokeswoman . . .

Little Richard was awake, talking to visiting relatives and making progress in his recovery at Los Angeles' Cedars Sinai Medical Center yesterday. "I wouldn't call him jolly, but he's very touched by the response from the community," said hospital spokesman Ron Wise. The flamboyant rock star-turned-minister was injured early Tuesday when his speeding sports car plowed into a telephone pole. He was listed in fair condition yesterday . . .

The Reagans understood that Maureen Reagan and her husband Dennis Revell, who had been cruising in the Mediterrean when the Italian cruise ship Achille Lauro was hijacked Monday, were safe, but Maureen telephoned the White House yesterday and spoke with the first lady to reassure her and say they would be in Europe for a while longer. The White House would not say where the couple is vacationing . . .

The "Heartburn" film crew wanted all the houses on 21st Street to have their lights on for filming still another segment of the movie last night. But when crew members stopped by the offices of Garfinckle, Liotta, Finkelstein & Dranitzke to ask for cooperation, they were in for a bit of a surprise. A representative of the law firm said it was fine if they photographed the building, but that the moviemakers should know that the firm represents Carl Bernstein, who has made a few problems for the movie.