Hello. I don't use Play Music and am not sure if that should work, but my Moto G does not come with a built in Music player app, as more heavily skinned brands like Samsung do.
Try a music player app from the Play Store like Rocket Player.
Neutron is apparently the best but expensive, Poweramp also.
Album Art Grabber will fetch album art.
It should play Windows WAV/ WMA and lossless files.
Android's Media Scanner should find the music files anywhere on internal or sd storage, apparently.