Deposed Philippine president Ferdinand Marcos spends nights in a hot, stuffy room in Hawaii, occasionally watching televised displays of his once-opulent life style, while his days are passed orchestrating a legal strategy stretching from Manila to New York, according to a friend who talks to him regularly.

Marcos still considers himself the legitimate president of the Philippines, according to the friend, and believes he is being denied the rights and dignity due a head of state.

As Marcos completed his 17th day in exile, the official appointed by the new Philippine government to investigate and recoup Marcos' "ill-gotten" wealth vowed in Washington to share all his findings with congressional probers pursuing the same goal.

Philippine Sen. Jovita Salonga and Rep. Stephen J. Solarz (D-N.Y.), chairman of a House Foreign Affairs subcommittee, vowed in a joint news conference to cooperate "in the effort to uncover the hidden wealth of the Marcoses and their cronies in the United States."

Earlier, in an interview, Salonga took issue with President Reagan's assertion in a breakfast interview with reporters last week that Marcos "was a millionaire before he took office" in 1966. Salonga displayed Marcos' income tax returns showing that he earned only $17,000 in 1960, and $66,000 in 1966.

"How do you account for the New York accumulation of $350 million in real estate?" Salonga asked rhetorically, pointing out that Marcos' yearly salary as president was less than $6,000.

In other developments yesterday:

*U.S. Ambassador to the Philippines Stephen Bosworth told President Corazon Aquino in a letter that the Marcos entourage was allowed to keep $300,000 in gold and $150,000 in bearer bonds that they brought to Hawaii "in their personal luggage." They were allowed to keep those assets because they declared them upon arriving and broke no U.S. Customs laws, Bosworth wrote in the letter, which was made available to The Washington Post. The Aquino government accelerated an investigation into reports that Marcos may have spirited tons of gold -- perhaps as much as $220 million worth -- out of the Philippines over the past three years, correspondent Jonathan C. Randal reported from Manila. Documents suggesting that Marcos considered selling several tons of gold were reported discovered in his private office in the Malacanang Palace, but a spokesman for the Philippines Central Bank said Governor Jose Fernandez had checked the books and found no gold missing over that time period.

*The Philippine government has been unable to account for $81 million out of $92 million in general economic assistance provided since 1982 by the U.S. Agency for International Development (AID). A General Accounting Office audit, which has not been released, has found that most AID money not targeted to specific projects could not be traced, according to sources close to the GAO. However, there was no immediate evidence the money was illegally diverted.

*Congressional investigators learned that Glyceria Tantoco, a close friend of Imelda Marcos and wife of the former Philippine ambassador to the Vatican, transferred $3.2 million last August from a bank in New York into an account of an offshore bank, and then to a Swiss bank account.

Tantoco was alleged in congressional hearings last year to be a "front" for the Marcoses' business activities.

*A senior Defense Department official said Marcos has been billed for the cost of flying him and 89 relatives and associates to Hawaii. The cost has been estimated by other Pentagon officials at $200,000.

Marcos and those investigating him continued their struggle yesterday over 1,500 financial documents he and his entourage brought to Hawaii -- records believed by Salonga and Solarz to be crucial to unraveling the sources and ex- tent of the deposed leader's wealth.

Although a federal judge in Hawaii issued an order on Thursday prohibiting the release of Marcos' documents to a "third party" on privacy grounds, the Reagan administration was set to argue in a New York court today that privacy considerations do not hinder its authority to give copies of the documents to congressional and Philippine investigators.

"We think it is lawful for us to pass them to Solarz and to the Aquino government through Salonga," a senior administration official said. "A formal request from a foreign government and a formal request from a subcommittee chairman should be sufficient basis to proceed in our opinion."

However, Stanton Anderson, senior partner in the Washington law firm representing Marcos, countered that the U.S. Customs Service has no legal right to hold onto Marcos' property -- including the documents -- for an extended period, and has no right to let others see it.

"Our primary claim is that the property belongs to the individuals who were on the airplane," he said. "The customs law says that they can take it and they can look at it, and if they the Marcos party haven't broken any laws, they have to give it back."

He added that the Customs Service should return the clothing and valuables of Marcos and his family, regardless of the fate of the documents.

Among the items Anderson wants given back to Marcos are 22 crates of freshly minted pesos, valued at over $1 million. "The president Marcos says they're his, they're campaign contributions from previous campaigns as allowable under Philippine law. Some of it was his personal funds."

The Philippine government is arguing in a lawsuit in Hawaii that the pesos rightfully belong to the Philippine government and were illegally taken out of the country.

The money and disputed documents might not have arrived in the United States at all, had Marcos known his destination when he fled Malacanang Palace almost three weeks ago, according to the American friend who talks with him frequently.

The friend said Marcos thought when the documents were packed that he was heading for his home province in the northern Luzon, with an overnight stop at the Clark Air Force Base. But Marcos was awakened at Clark after only an hour's sleep and hustled onto a U.S. C141 transport plane.

"He only knew he was going to Hawaii when he looked out and saw the stars weren't right," said this friend.

The deposed president appears in good health, despite suffering from a debilitating disease that affects his kidneys, and he jokes about returning to the golf course, the friend said.

But he said Marcos and his wife Imelda were upset at seeing a continuous stream of news reports about their lavish life style, their clothes, artwork and palatial accommodations.

"Of course it has an impact," the source said. "They try not to indulge in it. They watch television, they read press reports."