On the lyrics thing, it probably depends on how your using it. If you have a character singing their favorite song in the shower, your probably ok, since your making it known that they are existing song lyrics; that strikes me as somewhere between air use and just a pop culture reference. Now, if your using it as a bit of poetic language etc, but leaving its source ambigious, i dunno. You might simply make a footnote of it in the manuscript for now, and let the legals figure out the licensing when actual publication time comes, but I really dont know.