I think that it’s totally fine to use them in this stage. Especially because I think we’re all really influenced/inspired by music.
I just submitted something for copyright that had a lot of song titles/lyrics in it, and for the purposes of copyrighting, I dropped all the quotes. However, I think for publication you would be able to use them, you would just need to go through the process of getting permission. For one example, Let the Right One In is named after the Morrissey song Let the Right One Slip In, the publisher just changed the title because they felt it was too long, but it stayed “slip in” for a section title.
Also, a working title might help inspire you and then later on in the writing process, a new title might come to you. :)
I hope this helps, a little.
Happy writing, everyone!
