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.
XFCE is a fairly simple environment. If you can run Xfdesktop, Xfpanel, and Thunar, you have most of the experience. I would be ok running these over another window manager while the rest comes together. I used to use XFCE on an old iMac and Xfwm4 had a pretty bad memory leak so run XFCE over a different WM for a couple of years.
Yeah, I think labwc is a really good candidate for that.