It's seriously looking like trying to replace X11 with Wayland in whole is still too soon in 2017. I'm going to try a few other things, but here is what I've learned so far.

Weston w/ XWayland on Wayland: This works! But, of course it does. Weston is the reference implementation (read: prototype) of a Wayland compositing-client-window-manager hybrid. It works, but there's little available functionality.

SDDM 0.13 on Wayland: Wayland support! But... Not if you're running XWayland and you don't want to do serious hacking. When you compile Xorg as a pure XWayland module, it produces no executable. Instead, it just plops out xwayland.so, which works fine if you're running Weston. SDDM, however, assumes the presence of a native XServer and tries to launch it first, regardless of what's in sddm.conf. From sddm.log...

Gnome/Mutter on Wayland: First, I don't much care for Gnome, it's the poster child for unfocused development. Second, they're thrown their lot in with systemd. Gnome's only boon is the 3rd party desktops like Panteon and Budgie. So, my plan was to try elogind, but that appears to be a whole lot of systemd itself. elogind is not lightweight, like the consolekits are. I may still try it, but as a last resort.

KDE/QT on Wayland: This supposedly has support for xwayland and was looking promising. Especially, if I can use LXQt instead of KDE Plasma. However, LXQt doesn't have full Wayland support yet. And, in spite of Qt's talk about Wayland, it has similar problems to SDDM.

My attempts at running KDE Plasma on Wayland w/ XWayland have been fruitless so far. More infuriating is the lack of a proper log without installing gdb and tailing stuff in /proc. It appears to start on the drm interface and then just freezes me at the tty, no log, no stdout, no stderr. <grump> For now, it's irritating, so I may come back to it later.

LXQt on Wayland: As mentioned before, it's mostly Wayland ready. However, even if the desktop components were 100% Wayland, it still uses a third-party X11 window manager. OpenBox has no Wayland support and the problems with kwin from KDE were already mentioned.

Fedora 25 / Hawaii Linux: I may download these and look at how they are doing things. But, I suspect lots of band-aids are involved in their native Wayland setups. The Fedora 25 review I read explained that what works is excellent but, the things that do not are infuriating.

So, partial success... But it may be too soon to make this work on LFS without tons of customization. I still have a few more ideas to try.

You could use a lightweight wayland WM such as sway: http://swaywm.org/

It's more than just a WM that is the problem. I can't remember which ones exactly, but many have to do with XWayland. It's supposed to be a compatibility layer, but somethings don't work, or crash the compositor, etc.