The Lost Boys has multiple yearning songs and multiple contenders for "the" love ballad.
Arguably, "Belong to Someone" (and in a way "Lose Yourself") is Michael's yearning song. This song has every hint of being a yearning song, even down to the location in the show. There always has to be one for the MC in a musical... and this is his.
At the same time, "Time to Kill" is a yearning song and a love ballad through David's eyes. David just wants someone that he can talk to, bond with, and more. The little queer boy just wants to be able to flirt with the new boy in town, and that's where the yearning comes in. The yearning in itself is for connection, acceptance, and visibility. This is illustrated in "Time to Kill (reprise)" because you can see the yearning and its effects in David's POV (which is not included in the OBCR, so I will not go too in depth).
I could go on and on about potential contenders for these two boys, as well as my choices for the love ballad. It might be trademarked as "Now, Forever" if we're just looking at Michael and Star... but no one is talking about David completely opening his heart to Michael in "Take My Heart With You" and "Belong to Someone (reprise).
Upon request, I would be happy to elaborate on any of these perspectives, as these boys have garnered a lot of my thought space recently.