Right-wing parties in the Philippines asked estranged Vice President Salvador Laurel to join them Monday at the head of an opposition coalition that would be "strong enough to challenge" the government of President Corazon Aquino. "I am ready to subordinate all interests in order to effect a unity of the opposition," said rightist leader Sen. Juan Ponce Enrile after a breakfast meeting with Laurel, who two days earlier accused Aquino of incompetence and urged her to resign. Enrile, a former defense minister who was fired from the Cabinet when his aides were linked to a November 1986 coup attempt, said rightist and Moslem parties would hold further meetings "across the land" in order to forge an effective alliance.