If there’s a theme to many of this year’s song contenders, it’s getting in the final word.

In Bill Pohlad’s “Love & Mercy,” the film’s subject — Brian Wilson — provides the closing bookend with his song “One Kind of Love.” Hopeful strings and trumpet buoy Wilson’s keyboards and still-boyish vocals as he sings of unconditional love.

It’s both a throwback to vintage Beach Boys and a statement from a wiser, battle-scarred older man … aptly closing the curtain on a film that counterpoints Wilson in both his vintage years and embattled ones.

As another true-story drama, “Concussion,” fades to black, the soulful voice of Leon Bridges communicates a farewell message (“So Long”) for Will Smith’s character.

“Just seeing how a man that was trying to bring truth, and people were trying to bring him down because of that, that was the emotional vibe,” says Bridges. “Him not belonging … that’s what I was feeling.”

Bridges brought a world-weariness — belying his 26 years — to the story of Dr. Bennet Omalu (Smith), who goes head-to-head with the NFL after discovering the unique brain damage caused by concussions.

“I didn’t want to make a song that was so literal to the film,” says Bridges. “Really the song comes from a personal place … me going back home and people treating me different, saying that I don’t deserve to be where I’m at. Basically the song is saying that I love where I’m from, but maybe I need to leave, because I don’t feel the love. You know: ‘so long.’”

Paul Walker’s death necessitated a tearful farewell in “Furious 7,” which finished shooting after the actor’s fatal car crash in November 2013. Universal put a call out to 200 songwriters for a track that would underscore the film’s tribute to Walker — and 23-year-old Charlie Puth hit the right chord.

“I was a brand new writer, and I was trying to prove myself. I had a friend who passed away,” explains Puth (whose best friend in college died in a car crash), “and I always wanted to write a song for him, but really couldn’t figure out what it was going to sound like. When the opportunity to write for Paul came along, the situations were just so similar.”

Puth’s song, “See You Again,” offers an emotional, optimistic chorus (which he sings) over sensitive piano chords, alternating with verses rapped by Wiz Khalifa about the power of family.

“The song just flowed out of me,” says Puth. “It literally came together in 10 minutes.”

“Simple Song No. 3” — from “Youth” — plays perhaps the most internally significant role of any song in a film this year. Fictitiously written by Michael Caine’s aging composer, it is the summation of his life’s work and acts as catharsis — Caine’s final word — late in the film.

The elegant aria, performed by opera singer Sumi Jo and backed by the BBC Concert Orchestra, was written by real-life concert composer, David Lang, who also scored the film. “Everything leads up to this incredible moment when you see that song (performed),” says Lang.

“It has to (convey) this huge distance between where he was as a young man in love to where he is now as an old man in love. And the optimism of his youth has to be tempered with the incredible disappointment and heartbreak and the bittersweetness of having accomplished things when the person you love isn’t there with you.”

But not all the year’s more conspicuous original songs act as codas. To the contrary, the James Bond series has always opened with a tuneful wallop, whether it’s Shirley Bassey, Paul McCartney or Adele belting out the film’s signature tune over the opening titles.

“They told me the title of the film, and I immediately said I can’t write a song called ‘Spectre,’” says singer-songwriter Sam Smith of the latest Bond saga and his song “Writing’s on the Wall.”

“They (producer Barbara Broccoli and director Sam Mendes) agreed with me,” he adds. “The main thing they were looking for was an epic love song. They really wanted to concentrate on that underlying theme of love that’s in every Bond film.

“Me and Jimmy (Napes, his co-writer) wanted to make it like a diary entry of Bond’s, because I don’t think that’s been done before.”

“Writing’s on the Wall” became the first Bond song to hit No. 1 in the U.K.

Similarly, the happy, upbeat “Feels Like Summer” opens “Shaun the Sheep Movie,” which songwriter Ilan Eshkeri (who wrote with Tim Wheeler and Nicholas Hodgson) had to pen before shooting began, because the stop-motion animation sheep actually perform it in the film (they’re billed as the “Baa Baa Shop Quintet”).

“The whole film hinges on the song,” he explains. “The song reminds the farmer of his family, and sharing the sentiment of the song brings them all together.”

Keegan DeWitt also had to write the title song for “I’ll See You in My Dreams” in advance of shooting, as the pool man-turned-songwriter (Martin Starr) sings it to Blythe Danner late in the film.

“I’m not a great topical songwriter,” says DeWitt. “It’s not on the nose. It’s not about facing death, it’s this nuanced thing of how to truly be alive in all these different stages of your life. I wanted it to be a song about people who may be in your life for a moment, and may not be in your life for other moments.”

Movie-song vet (and seven-time nominee) Diane Warren collaborated with Lady Gaga on “Til It Happens to You,” from the documentary “The Hunting Ground,” about the epidemic of sexual assault on college campuses. Gaga, who was raped at 19, says, “I was a victim when I began this with Diane, and I ended the process a survivor and a fighter.”

Gaga’s contribution turned a sad song “into a fierce anthem,” says Warren, who was abused as a child. “It became a f*%#-you song. It’s making people feel less alone. I’m hearing from people who say the song has given them strength.”

Adds Gaga: “We want people to feel empowered.”

For another documentary, “Racing Extinction,” about the shocking number of disappearing species in the world, songwriter J. Ralph wrote two songs: “Manta Ray,” based on the piano waltz that dominates the score, and “One Candle,” an anthem “to inspire people that they have the power to make a difference through everyday changes.”

He co-wrote “One Candle” with Sia, who sings it: “When you’re talking about shouting from the rooftops to get the attention of the world, there was no better choice than Sia,” Ralph says.

“Manta Ray,” which he calls “a haunting meditation, to get people thinking,” has lyrics and a vocal by Antony. “If I had to pick one voice to represent the fate of humanity, it would be Antony. He has the most incredible intimacy and presence.”

The power ballad “Love Me Like You Do,” sung by English songstress Ellie Goulding in “Fifty Shades of Grey,” reached No. 3 on the U.S. charts and spent four weeks at No. 1 in the U.K.

Songwriter Savan Kotecha (who wrote it with Max Martin, Ali Payami and Ilya Salmanzadeh) recalled the sequence in which Dakota Johnson takes a helicopter ride with Jamie Dornan: “That was the scene that spoke to us most. We knew what the atmosphere of the track should be.”

Director Sam Taylor-Johnson talked to the songwriters, he says, and after coming up with the title “Love Me Like You Do,” they pursued a lyric about “this innocent girl who is not asking (the film’s tycoon protagonist) to completely change. She’s still fascinated by this guy and the passion is so deep in her.”