Looking for a quick answer, are made up song lyrics aloud when applied in a story?

Yes. I've read stories where are lyrics there, bạn just have to tell the song it's made bởi someone else and identify the author. Hope I helped you

I did this in one of my fanfics (a Harry Potter fanfic). My 2 Original Characters were musicians and I quoted songs they performed.
Sometimes, songs and lyrics are almost inevitable. Take fandoms such as the Blues Brothers, musicians and singers. I am also a người hâm mộ and those of us that write in that fandom do use songs and lyrics, as part of the storyline.

My policy is to quote the song when relevant to the plot and QUOTE their authors and performers. As most of the time I write under the influence of music, I also quote the piece that had accompagnied me in "author's notes" at the end of each chapter (whenever relevant). I also provide the YouTube link to the piece, so that readers can read the story and listen to the songat the same, to add atmosphere. I had some readers that had written back to me that they had checked the link and were very happy to have the oppportunity to know a piece hoặc a band hoặc a song hoặc a singer.