The Xfce Wayland road-map on the project’s Wiki has been updated a few times over the past two weeks, namely around the desktop panel plug-ins and applications support for Wayland. There still isn’t a firm timeline or release where they expect to have a complete Xfce Wayland transition complete, but ultimately are aiming to have a native Wayland experience that doesn’t depend at all on XWayland and will be using wlroots as part of its compositor. Many Xfce panel plug-ins are working under Wayland as are a number of Xfce’s own applications.
Do note, though, that there’s no certainty at all yet that Xfce will transition to Wayland completely. As the roadmap clearly states:
It is not clear yet which Xfce release will target a complete Xfce Wayland transition (or if such a transition will happen at all).
So, the future of Xfce on Wayland is not yet set in stone – but with X.org having effectively been abandoned, I doubt Xfce will have much say in the matter.