I was talking with a friend who wants to write a musical. He wants to write the music if I write the script. I got an idea about a singer's journey to fame. There would be numbers with the ensemble and supporting cast, but the thing that would set apart the musical from others is that many of the songs would be ones the lead writes and performs in the story. There would be one song that he's building on throughout the entire musical and it would close with the full live version. The hook of the song would be the musical's message. So what I have in terms of plot so far isn't much but it's something to go on. I need help creating supporting roles because so far the plot is only driven by two characters, and I want more people to have opportunities to have major roles. The main character is a singer named Gill, is a songwriter who dreams of making it big. He starts a livestream channel to perform online concerts in his room. A girl Gill knew in high school named Madysin, who had a crush on him, notices him again when Gill starts attracting attention on his livestreams. Madysin is a writer and she's just realized that Gill inspired her novel with one of his songs and she wants to contact him so she can thank him, but she can't get ahold of him. Eventually, in the second act, Gill would regularly perform onstage with the ensemble playing the concert audience. He would get the real audience to sing along too, but the ensemble members play the fans who have already heard the album versions of the song and know all the words. All the music he performs (i.e, the in-story ones) would be live, whereas the songs that tell the story (ones that the other characters sing) would be part of the musical. He would notice Madysin (though not in a romantic way, as neither are interested in each other at this point) and they would become actual friends like Madysin always wanted. So, I need to come up with an actual plot with a more or less even male-female cast and opportunities for the ensemble to shine (aside from the scenes where Gill performs live) and a proper antagonist or two. Suggestions?