Now that they've settled the financial questions of their corporate marriage, Matsushita Electric Industrial Co. and MCA Inc. will be turning their attention to how the deal plays in Washington and with the American public.

Sony Corp.'s $4.8 billion buyout of Columbia Pictures and Mitsubishi Corp.'s $846 million purchase of Rockefeller Center last year were headline news across the country, and generated a flurry of criticism from those concerned about Japanese purchases of high-profile American companies and cultural assets.

Determined to avoid a rerun of the same debate, MCA and Matsushita last month jointly hired a team of well-connected Washington lobbyists and public relations executives to blunt potential opposition to the buyout even before it was certain. The move was highly unusual: Parties negotiating an acquisition typically wait until a deal is made before agreeing on representation.

The public relations firm they hired is headed by Jody Powell, President Carter's former press secretary, who said his company's Washington and New York offices were contacted "virtually simultaneously and independently" by MCA and Matsushita. "The decision to hire us was arrived at by the two respective clients since their discussions {were} entirely friendly. They both thought this would be an effective way to implement this {deal}," Powell said.

For legal muscle, MCA and Matsushita enlisted the law firm Akin, Gump, Strauss, Hauer & Feld, whose partners include Robert Strauss, the former chairman of the Democratic National Committee. Strauss is a member of MCA's board, as is former senator and former White House chief of staff Howard H. Baker.

Matsushita is already working to overcome opposition from several quarters unhappy about its trade and foreign policies. In 1984, Matsushita and other Japanese TV manufacturers were cited by the International Trade Commission for selling TV sets at a loss in the United States in an effort to gain market share -- a violation of U.S. trade laws that prohibit "dumping." The company also has faced charges from U.S. cellular telephone producers and video-display manufacturers that it is selling those products well below cost.

Yesterday, the purchase drew strong criticism from Edgar Bronfman, president of the World Jewish Congress, who said that Matsushita is a "slavish adherent of the Arab-led economic boycott of Israel." The accusation is apt to be an emotional one in Hollywood, where Jews founded and continue to hold prominent positions in many of the major studios.

Matsushita President Akio Tanii, speaking at a press conference in Japan, denied yesterday that his company boycotts Israel. "Matsushita has no special attitude toward any nation and this won't change," he said. A source close to Matsushita said yesterday that its products are available in Israel, but are sold by an American distributor, not by Matsushita directly. The source said the company sells in the Arab world through similar indirect means.

MCA President Sidney J. Sheinberg said yesterday that MCA would continue to honor U.S. law, which proscribes American firms from boycotting Israel. The company distributes its films and TV programs in Israel through a joint venture with two other major studios.

Other questions likely to be raised by the MCA buyout include:

Foreign ownership of film and television production. The buyout means that four of Hollywood's seven major studio are now controlled by foreign interests. Jeff Faux, president of the Economic Policy Institute, a Washington think tank that has been critical of Japanese trade policies, suggested that the sale could lead to a change in programming, through a process of self-censorship. "It's inevitable that producers and directors will be sensitive to Japanese interests and sensibilities and things that criticize the Japanese may get a second look," Faux said. " ... It's simply a fact of life that he who pays the piper calls the tune."

Sheinberg, however, called this "a false issue. No one will tell MCA what to make and what not to make. It's that simple." He noted that MCA resisted intense pressure by religious groups that wanted Universal to withhold release of its controversial film "The Last Temptation of Christ."

The future of the Federal Communication Commission's financial interest and syndication rules. The TV networks -- ABC, NBC and CBS -- have been lobbying furiously to overturn rules that since 1970 have prevented them from investing in Hollywood production companies or sharing in the revenue from reruns of network programs. The rules, however, allow the MCA and Matsushita hookup.

The networks were quick yesterday to attack as unfair a policy that allows links between U.S. moviemakers and foreign home-video manufacturers but outlaws them between American producers and TV networks. Laurence A. Tisch, president of CBS Inc., said the purchase "accelerates the dizzying pace of consolidation in Hollywood." He said "there is no more eloquent testimony for repeal" of the syndication rules, which he said give foreign-owned studios advantages over the three American networks.

Tisch's remarks were echoed by Rep. John D. Dingell (D-Mich.), chairman of the House Energy and Commerce Committee, who said, "Our regulatory system should not protect foreign-owned companies at the expense of American enterprises."

The future of proposed new U.S. standards for high-definition television. U.S. officials and industry executives oppose adoption of the Japanese standards for the new technology, in part to encourage home-grown manufacturing.

Those standards will affect everything from the cameras and editing equipment used to make movies and TV programs to the wiring and microchips inside the next generation TVs. But as Japanese "hardware" makers such as Matsushita and Sony Corp. buy U.S. producers of video and music "software," such efforts may be undermined as foreign owners assert their market power to encourage adoption of Japanese HDTV standards.