That's not entirely correct. Neither X11 nor Wayland are GNU projects. I don't own a device that I can install Ubuntu Touch on but I have had a poke around the image and repo and I can tell you that much of the GNU operating system is either already installed or can be installed. Like Harmattan, it uses Embedded GLIBC, hence why libhybris is needed for the Android drivers.

As far as I am aware, Canonical have not confirmed that SurfaceFlinger will be used/required on all Ubuntu Touch devices. So long as certified apps are based on Qt/QML I don't think it matters what display server is running underneath. If rumours are to be believed, Canonical are developing their own display server. X.Org and Wayland already appear to be available so hopefully too much effort won't be needed to get them up and running.

Unlike Mer, Ubuntu Touch is using recent GPLv3 packages (the installed version of coreutils is 8.13) and aren't going down the route of Tivoization which is a big plus IMHO.