Motif and CDE are maintained in ports. I'm working on a cde-devel port as well, still need to get pkg-plist right before committing it.
Openlook was removed because it didn't support 64-bit, it segfaulted on 64-bit FreeBSD. I recall seeing some 64-bit patches for openlook about ten or more years ago but I can't find them anymore. If I can find, or someone sends me, the 64-bit patches I'm certainly willing to bring it back. To create new 64-bit patches from scratch would be a multi-month project. I still have the distfiles and the ports (locally) if anyone is willing to put the work to port it to 64-bit.
Openlook only ran on 32-bit Sparc. Sun shipped CDE with Solaris when Sparc64 was produced. Later on, as of Solaris 10, Sun dropped support for CDE, shipping Gnome2 with Solaris. Openlook and XView were never written to run on 64-bit platforms.