The State Department yesterday welcomed Ayatollah Ruhollah Khomeini's order that clergymen be allowed into the U.S. Embassy in Tehran to celebrate Christmas with the 50 American hostages held there since Nov. 4.

"The State Department welcomes this development," said Merton Bland of the department's Iran Working Group.

"We are very much in favor of getting some ministers in to the hostages prior to or on Christmas and have been working towards that end for a couple of weeks."

Although a student spokesman at the embassy in Tehran said that no clergymen had been decided on yet, informed sources here said four American men had emerged as leading candidates for the Iran trip.

They include:

The Rev. William Sloane Coffin, a United Presbyterian minister and fomer Yale chaplain who gained prominence as a Vietnam antiwar activist. He is now pastor of the Riverside Church in New York City.

The Rev. William M. Howard Jr., president of the National Council of Churches and executive director of the Black Council of the Reformed Church in America. Howard lives in Princeton, New Jersey.

Bishop Thomas C. Kelly of Washington, general secretary of the U.S. Catholic Conference.

Bishop Thomas Gumbleton of Detroit, leader of Pax Christi, a Catholic peace movement.

Coff and Gumbleton appeared to be under consideration because of their credentials as pacifists while Howard and Kelly head the leading Protestant and Catholic umbrella organizations in the country.

Other names mentioned have been Archbishop John Quinn of San Francisco, the president of the U.S. Catholic Conference, and Bishop Paul Moore, Episcopalian bishop in New York City.

"This was set up by the Iranians and we will be quite happy to cooperate with any person so named with passports or any other help required," Bland of the State Department's Iran Group said.

He said the department had not recommended any particular names, but that it was "logical" to choose from the Protestant and Catholic umbrella organizations.

Two Univeristy of Kansas professors active in the anti-shah movement, in the United States, Norman Forer and Clarence Dillingham, have been negotiating in Tehran which clergymen will attend. They reportedly have the names of several American ministers willing to fly to Iran for the ceremonies.

Asked in a telephone interview whether he would be going to Iran, Gumbleton said last night, "I don't know, everything is up in the air." we face today," the president said. "The lives of over 50 innocent peo