[uup]

It's actually pretty common to separate music and lyric writing. For instance, I'm sure you recognize names like Puccini and Verdi as famous opera composers. It was very common for someone else to write the "lyrics" to their operas (called libretto in opera). For instance, both Puccini and Verdi had Francesco Maria Piave write libretto for multiple operas. And yet, we still think of Puccini and Verdi as having written their respective operas.