Using any copyrighted materials in your project, beyond brief excerpts, may only be used with written permission from the copyright holder.
Copyright is automatically given as soon as the work is put in a fixed tangible format. There is no requirement that the work needs to be published or registered to be protected.
Even though registering your copyright is not required, you may wish to register it anyway. Registering your copyright with the Library of Congress does provide advantages. Additionally, although you can register your copyright at any time during the life of the work, if you register within the first 3 months or prior to a claim of copyright infringement, you may be eligible for statutory damages and attorney fees if you have a claim of copyright infringement.