Janet, I was going to lay out some best practices, but I got sidetracked on other projects.
To address one directive, you really should duplicate your entire library – or at least a portion there of – and first do a trial of Songkong WAV to FLAC with embedded metadata. Keep your original library untouched. Because you are pleased with the current state of your library, you do not want to make destructive changes without a path to undo those changes if you are not satisfied.
AJ