My daughter is on her second optional floor routine and both experiences have been the same.
1. The coach makes a list of 5-7 songs for her to listen to and she either makes a choice or offers up her own suggestions. At some point, both gymnast and coach agree that the song is right and mom purchases the music.
2. Mom pays choreography fee which gets choreography by one of the two main coaches as well as 2 private lessons to learn the routine. If you need additional time, mom purchases private lessons. You can also choose which of the two coaches does your routine if you have a strong preference.
3. At some point, coach will schedule the privates. She will have already mostly hashed out the choreography although there is some wiggle room. Tumbling passes aren't set in stone at this point. Even direction of landing can be fudged some. The more experienced older gymnasts have more say in their choreography but if you're DD's age/experience, you shut up and learn your choreography.
4. The routine gets tweaked all season long. This leap isn't working so substitute in this one. This tumbling pass was upgraded so let's switch it up. Sometimes even this segment would look better here so let's switch this part and that part. I don't think my DD performed the same routine twice until the last two meets of the season.