On Friday, the head of the Office of Government Ethics, Walter M. Shaub Jr., said in a letter that the announced schedule had placed “undue pressure” on the office to rush its reviews of nominees. He added that there was no precedent in the office’s four decades for the Senate holding hearings before such reviews were complete.

Senator Chuck Schumer of New York, the new Democratic leader, has accused the Trump transition team of colluding with Senate Republicans to “jam through” nominees. Republicans say they simply want to allow the incoming president to install his team as quickly as possible.

In an interview on Sunday on CBS’s “Face the Nation,” the Senate majority leader, Mitch McConnell, Republican of Kentucky, played down the concerns as “little procedural complaints,” which he attributed to Democrats’ frustration at having lost the election. “We need to sort of grow up here,” he said.

The Democratic playbook

Complaints about the process may not resonate with the broader public, though they will surely continue. In either case, Democrats view the hearings as an opportunity: How will the nominees parry questions about Mr. Trump’s most explosive campaign pledges, like barring Muslim immigrants and promoting torture?

“Where will they come down?” Mr. Schumer asked in an interview.

Democrats have signaled that some nominees — like Representative Tom Price of Georgia, the choice for health and human services secretary and a vocal opponent of the Affordable Care Act — will face more hostile questioning than others.

But after a stunning election victory that saw Mr. Trump seize the mantle of populism, becoming a hero to working-class white voters and promising to “drain the swamp,” the Democrats hope to establish a different theme: Mr. Trump’s nominees would become by far the wealthiest cabinet in modern history. Some, like Ms. DeVos and Andrew F. Puzder, the pick for labor secretary, are notable Republican donors, far removed from the lives of many of Mr. Trump’s voters.