For anybody else following along, XFCE is working on Wayland support. In fact, the only component not already supporting Wayland in Git is XFWM4 itself. Wayland will ship officially as part of the 4.20 release.
They are creating an abstraction library that will allow XFCE to support both X and Wayland. Other desktop environments are going to use it as well.
boredsquirrel