Here are some of the people who are speaking at the 2016 Republican National Convention in Cleveland and some who've opted to skip the event. (Sarah Parnass,Danielle Kunitz/The Washington Post)

Donald Trump’s convention will feature an eclectic mix of cultural figures, including the first woman to command a space shuttle mission, survivors of the attacks in Benghazi, Libya, in 2012 and an underwear model.

But while several Republican Party establishment figures will take the stage next week in Cleveland, the national convention to officially make Trump the party’s presidential nominee will be devoid of some of the GOP’s most seasoned leaders and brightest new stars.

Republican officials on Thursday released a long-awaited list of convention personalities billed as “non-conventional speakers” who emphasize “real world experience.”

The convention’s theme will be Trump’s campaign slogan, “Make America Great Again,” with a core focus on national security, immigration, trade and jobs.

The program includes more than a dozen current and former elected officials, including the leaders of the party’s congressional wing, House Speaker Paul D. Ryan (Wis.) and Senate Majority Leader Mitch McConnell (Ky.).

A whole host of influential Republicans have decided not to attend next week's Republican National Convention in Cleveland. (Peter Stevenson/The Washington Post)

A handful of governors and other lawmakers are scheduled to give addresses, including former primary opponents Sen. Ted Cruz (Tex.), Wisconsin Gov. Scott Walker, New Jersey Gov. Chris Christie, former Arkansas governor Mike Huckabee and retired neurosurgeon Ben Carson.

“There’s going to be a unified convention,” Trump spokesman Jason Miller told reporters Thursday, adding that the announced agenda was only a partial list of speakers. “People are going to be united behind Mr. Trump.”

The unusual collection of nonpolitical speakers seems designed to broaden Trump’s appeal. Roster names include retired astronaut Eileen Collins, the first female space-shuttle pilot and mission commander; Mark Geist and John Tiegen, two survivors of the 2012 attacks on a U.S. diplomatic outpost in Benghazi; and Antonio Sabato Jr., a former Calvin Klein underwear model, soap-opera actor and reality-television star.

Some sports figures will take the stage here, including pro golfer Natalie Gulbis and Ultimate Fighting Championship President Dana White.

Tim Tebow, a 28-year-old former National Football League quarterback and Heisman Trophy winner, was expected to speak at the gathering, according to GOP officials. Tebow is admired by many conservatives because of his outspoken evangelical Christian beliefs.

But Tebow said Thursday night in a Facebook video that he would not be speaking: “It’s amazing how fast rumors fly. And that’s exactly what it is, a rumor.”

But some sports heroes of decades past whom Trump has said he would like to see at the convention — such as former Indiana University basketball coach Bobby Knight and boxing promoter Don King — are not listed as speakers.

Also notably absent from the list of speakers was Indiana Gov. Mike Pence, who was identified by Trump allies Thursday as the candidate’s likely vice presidential pick. If chosen, Pence would deliver an acceptance speech after being formally nominated for vice president.

Two other vice-presidential finalists, Christie and former House speaker Newt Gingrich (Ga.), are listed on the program, as is Sen. Jeff Sessions (Ala.), who also was vetted as a vice-presidential prospect.

Not speaking in Cleveland are the GOP’s past two presidential nominees, former Massachusetts governor Mitt Romney and Sen. John McCain (Ariz.), as well as its only two living former presidents, George W. Bush and George H.W. Bush. None will be in Cleveland for the week-long festivities.

Also excluded from the speakers list are many of the party’s more diverse rising stars, including South Carolina Gov. Nikki Haley, New Mexico Gov. Susana Martinez, Sens. Marco Rubio (Fla.) and Tim Scott (S.C.), and Rep. Mia Love (Utah).

By contrast, the Democratic National Convention the following week in Philadelphia is expected to feature a full assortment of party stars — past, present and future — including President Obama, first lady Michelle Obama, Vice President Biden, former president Bill Clinton, and Sens. Elizabeth Warren (Mass.) and Bernie Sanders (Vt.).

The disparity in political star power between the conventions speaks volumes about the state of the two parties, with Republicans divided over their controversial new standard-bearer.

Looking ahead to Philadelphia, Republican strategist Rick Wilson said of the Democrats, “Bill Clinton, Hillary Clinton, Barack Obama, Michelle Obama, Elizabeth Warren — they’re all going to be out there swinging for the fences. But the Republicans, it’ll be like a hostage video of people forced on stage.”

The Cleveland convention will be orchestrated to help expand Trump’s appeal to the general electorate. To that end, several members of his family are expected to give speeches, including his wife, Melania, and his four oldest children: Donald Jr., Ivanka, Eric and Tiffany.

In addition, other speakers who have known Trump and his family through the years plan to take the stage. They include Haskel Lookstein, a rabbi in New York who converted Ivanka Trump to Judaism; Tom Barrack, a wealthy California-based investor who has worked with Donald Trump on real-estate deals; and Kerry Woolard, the general manager of Trump Winery in Virginia.

With the public on edge following a spate of shootings by police and last week’s killing of five officers in Dallas, Trump has sought to brand himself as the law-and-order candidate. Some speakers at the Cleveland convention could help him make that case, including Milwaukee County Sheriff David Clarke, a Democrat who is an outspoken critic of the Black Lives Matter movement and is a frequent Fox News Channel guest; former New York mayor Rudolph W. Giuliani; and two female attorneys general, Pam Bondi of Florida and Leslie Rutledge of Arkansas.

Several early Trump backers are being rewarded with convention speaking slots, among them Jerry Falwell Jr., the president of Liberty University, a college founded by his late televangelist father. Falwell campaigned frequently at Trump’s side leading up to the Iowa caucuses.

But one especially prominent Trump surrogate is not listed as a speaker: Sarah Palin, a former Alaska governor and 2008 vice-presidential nominee, who has garnered mixed reviews for her campaign-trail appearances supporting Trump.

Here in Cleveland, the Republican National Convention’s Rules Committee convened early Thursday and met late into the night to review the 42 rules governing the party structure and the selection of a presidential candidate. The big undecided issue remains whether or not to continue binding convention delegates to the results of caucuses and primaries or to unbind delegates and allow them to vote however they want.

Another subject of talks, which eventually collapsed with no resolution, centered on whether to return the party to closed contests — meaning that only Republicans could vote in presidential caucuses and primaries. A group led by Ken Cuccinnelli, the former Virginia attorney general, also wanted to make other changes to party operations.

Republican National Committee Chairman Reince Priebus and several members of the party’s leadership generally support the idea of reverting back to closed contests by awarding more convention delegates to states that hold closed contests.

Cuccinnelli said he proposed giving 20 percent more delegates to states that opted to hold a closed contest. Priebus and his team considered the offer, cut ultimately declined, according to people familiar with the talks.

Ed O’Keefe and Dan Balz contributed to this report.