President-elect Donald Trump was elected with a mandate last week. He's now using it to challenge Republican senators to confirm his Cabinet picks, who range from the predictable to outright unconventional.

Trump started off by fleshing out his incoming administration with conventional figures. Susie Wiles, a respected GOP strategist who helmed his successful campaign, would make sure the trains run on time as his chief of staff. Florida Sen. Marco Rubio, an institutionalist who has hewed to Trump's "America First" agenda, would handle diplomacy as secretary of state. Former Immigration and Custom Enforcement head Tim Homan would return to a border enforcement role.

Then, he announced nominees who caught lawmakers off guard. Fox News host and U.S. Army veteran Pete Hegseth was tapped to lead the Pentagon. Former Hawaii Rep. Tulsi Gabbard, a Democrat-turned-Trump ally who previously met with Syrian strongman Bashar al-Assad, would be the director of national intelligence.

And to top it off, Florida Rep. Matt Gaetz would lead the Justice Department despite a House Ethics Committee investigation into allegations of sex trafficking a 17-year-old girl. He's denied the claims, and the Justice Department -- the agency he'd run if confirmed -- declined to bring charges after a similar inquiry.

Now, as a new Senate majority prepares to take control in January and work with the president-elect, Trump is flexing, betting that Republicans on Capitol Hill will go along after touting the need for unity.

"He's appointing the exact people he wants, knowing that he can get him confirmed if he has enough Republicans," said former Senate GOP aide Brian Darling. "And I have a feeling that they'll get confirmed by virtue of the fact that Trump's threats to primary Republicans in the past have really scared a lot of never Trump Republicans into retirement and led to a lot of them losing primaries."

"He's challenging them," Darling said. "I think they all get confirmed. Not without controversy, but I think they get confirmed."

The recent nominations of Hegseth, Gabbard and Gaetz were not on Washington's radar prior to their announcements, with Gaetz in particular raising eyebrows shortly after Trump rolled that pick out.

Hegseth and Gabbard "probably" get confirmed, one current Republican Senate aide predicted, while Gaetz is "on the bubble."

"I don't think it's a serious nomination for the attorney general. We need to have a serious attorney general and I'm looking forward to the opportunity to consider somebody that is serious. This one was not on my bingo card," Alaska Sen. Lisa Murkowski, a key GOP Swing vote, told reporters after Gaetz's nomination was announced.

"This is why the Senate's advise and consent process is so important. I'm sure that there will be many, many questions raised at Mr. Gaetz's hearing," added Maine Sen. Susan Collins, another moderate Republican.

The reality of the upcoming confirmation battles is hitting Republicans who just wrapped up the contentious and high-profile process of minting a new Senate leadership team.

"Ninety-nine percent of the discussion has been, who's going to be the new leader, what are the rules going to be, how do we work with the transition team. Getting down into the weeds on specific nominees, I've heard no talk about that," the current Republican Senate aide said.

Earlier Wednesday, the new Senate GOP heads were projecting the need for unity and cooperation with Trump.

"What we are going to do is make sure that we are processing his nominees in a way that gets him [Trump] into a position so he can implement his agenda," South Dakota Sen. John Thune, Senate Republicans' leader starting next year, said Wednesday before Gaetz's nomination was announced. "Obviously we are going to look at, explore all options to make sure that they get moved and that they get moved quickly."

Nevertheless, the more controversial picks stand out from some of the more conventional Cabinet options like Rubio and could spark some friction between at least some Republican senators and a president-elect who is undoubtedly his party's leader.

"When you've got nominees like Marco Rubio who's gonna fly through the Senate with more than 90 votes, and then you get some of these other folks who are likely staring down party-line votes, it's hard to say," one outside adviser to a member of the new Senate leadership team said when asked if some of the more controversial picks could get confirmed. "Some of these nominees definitely have more work cut out for them than others."

"I think [Trump] feels empowered, for sure, to seek out and govern the way he ran, and in many ways, like these picks reflect that," the person added. "As a body, I believe they will be working closely together. They got a lot they gotta get done in the next two years, hopefully four years."

Some operatives downplayed the idea that Trump was challenging Senate Republicans, arguing that Trump was merely pushing for his administration to be staffed after he was elected by voters hungry for change.

"He does not look at this like, 'I need to find common ground with these guys.' It's that 'these are my picks. This is how it works. I want my people.' It's not like he's daring them. It's not like he thinks, 'I'm going to push the envelope and tout somebody.' He's saying, 'these are who I want. The people told me to come in and make changes, and I'm going to do it,'" said Sean Spicer, Trump's first White House press secretary.

Trump could also go around the Senate -- before leadership elections were held, he insisted that Republicans should grant him the ability to make temporary appointments while Congress is out of session, a demand that most of the Senate GOP quickly got on board with.

But should Trump submit his nominees through the typical confirmation process, he would be putting up his dominance within the Republican Party and desire overall for GOP unity against some lawmakers' consternation with some of his more contentious picks.

"He is certainly saying, 'I am in charge. I won the popular vote. I won the Electoral College, and we need to be united,'" said Martha Zoller, a conservative radio host who was a Republican Senate aide during Trump's first term.

Still, Zoller said, "I think there will be more than one of these nominees that we might go to the No. 2 choice."