The telephone numbers and addresses (geographic and Internet) for U.S. government agencies are listed in the Federal Yellow Book (see "Yellow Books") and the Federal Staff Directory (CQ Press).
You can link to Federal agency websites through USA.gov, or just put the name of the agency into a good search engine.
Biographical material on selected government officials is available from Carroll Publishing and, sometimes, the agency's own site. You can also search an online news database.
Closings: To see if Federal government agencies were closed on a particular day, check the Operating Status & Schedules page posted by the Office of Personnel Management.
Speeches & Transcripts: Links to speeches by agency officials currently in office that have been posted for free on the Web are generally available through the relevant agency's Web site. You can also call the agency or the speaker's office. They may be willing to provide a copy.
Otherwise, you can try to find transcripts, recordings and/or videos using search engines. See also the resources discussed in the Speeches entry.
Presidential Authority: The President of the U.S. is the head of the Executive Branch, and the President is authorized to appoint or fire the head of most U.S. government agencies. However, the President is probably not allowed to tell agencies how to rule on particular cases. See Who's in Charge? Does the President Have Directive Authority Over Agency Regulatory Decisions? 79 Fordham Law Review 2487 (2011).