Ms. Lalama arrived at the first opening number rehearsal carrying a notebook scribbled with X’s and O’s grouped into formations. “I come from a football family, and this is how I draw dance patterns” she told the gaggle of bright-eyed high-school students standing in front of her in spandex pants and dance shoes. “Give this 150 percent!” Ms. Lalama shouted, as the students prepared to run through the number again.

The opening number is always a cheeky mega-mix of contemporary Broadway hits woven together with aplomb by the musical director Michael Moricz. This year, the contestants quickly transitioned from harmonizing the teen angst of “Dear Evan Hansen” to stomping out the Celtic beats of “Come From Away.”

The group number is followed by several mash-up medleys of solos that students performed to win their regional competitions. The teenagers are in full school-production costume — whether Phantom or Wednesday Addams — and comedic juxtapositions are introduced; a proud Don Quixote of “Man of La Mancha” may interact with a nebbishy Seymour of “Little Shop of Horrors” in the context of a single number.

Because the number of participants has swelled in recent years, not every student can appear in a showcase medley. “We’d be there for four hours,” Mr. Kaplan said. So, for the second year in a row, he devised a group number that gives the remaining students a chance to woo the judges. (This year it was a tribute to shows Mr. Nederlander had produced or presented.)

Because of the rapid rise of one Jimmys alumnus, Eva Noblezada, there is new pressure on the participants: the chance to suddenly land a Broadway role simply by singing on the Minskoff stage.

Ms. Noblezada, 21, who currently plays Kim in “Miss Saigon” at the Broadway Theater and was nominated for a Tony this year, was first spotted by Ms. Rubin, the casting director, who served as a judge in 2013. “Obviously, I wouldn’t have gotten ‘Saigon’ if it wasn’t for that,” Ms. Noblezada said. (She did not win a Jimmy Award.)

“I hear Eva’s break talked about among the kids a lot,” Ms. Lalama said. She also mentioned Ryan McCartan, another former contestant who last year landed a major role on Fox’s television adaptation of “The Rocky Horror Picture Show.”