After a trial run involving a COPR repo , I had written earlier indicating that I started doing real builds of Xfce 4.12 packages for EL-7 . This is now complete and I have now submitted a update - a mega update containing 53 packages total.
Three points about the update
- libxfce4ui obsoletes libxfcegui4
- (plugins using libxfcegui4 were never built for EL-7)
- xfce4-pulseaudio-plugin obsoletes xfce4-mixer and xfce4-volumed
- (xfce4-volumed is not even in the repos)
- xfce4-pulseaudio-plugin uses pavucontrol as sound mixer which is unavailable in EL-7 at the moment.
 Link to mailing list
 link to COPR repo email
 Link to "package building" announcement