Mr. Freedman frequently discussed the possible Australia trip with another lobbyist, Richard Smotkin, who has longstanding ties to Mr. Pruitt. Mr. Smotkin also helped organize Mr. Pruitt’s December trip to Morocco, and then four months later signed the $40,000-a-month contract to represent an arm of the government of that North African country.

Michael Brune, executive director of the Sierra Club, said in a statement, “It’s no wonder these emails had to be forced out by a court: They expose the fact that corporate lobbyists are orchestrating Pruitt’s taxpayer-funded trips to push their dangerous agendas.”

The emails with Mr. Freedman were among a collection of 6,337 pages of correspondence between corporate representatives and top political appointees at the E.P.A. Most were sent to Millan Hupp, a top political aide to Mr. Pruitt. Ms. Hupp also worked with Mr. Pruitt as a political assistant when he was Oklahoma’s attorney general.

Ms. Hupp served as a gatekeeper for Mr. Pruitt with companies and organizations interested in getting on his calendar or inviting him to an event, the emails indicate. Those companies have included the coal producer Peabody Energy and Koch Industries, the conglomerate controlled by the billionaire brothers David and Charles Koch, as well as dozens of others, with a particular emphasis on fossil-fuel-related firms and chemical industry and agriculture groups such as the American Farm Bureau.

Mr. Freedman is not registered as a lobbyist for the government of Australia, nor is he currently registered to lobby on behalf of any foreign or domestic clients in the United States, according to records on file with Congress and the Department of Justice. They show that a now-inactive firm he had formed with Mr. Manafort was last registered to lobby in the late 1990s, when it represented the government of Nigeria and the Argentine politician Alberto Pierri.

Mr. Freedman’s associates say he continues to advise international clients in various capacities that do not trigger lobbying disclosure requirements.

In the emails, Mr. Freedman offered Ms. Hupp a series of suggestions as to whom Mr. Pruitt could meet with on the trip to Australia. Mr. Freedman said he had already been talking to top government officials there to get the planning started.