There no reason (anymore, from a Universalist perspective) that a minister without ministerial fellowship in the UUA can't serve a UU congregation. There are some denominational oddments around inclusions in directories -- unimportant to the living -- so I have to think the reason to note such in our once-print, now-online directory is to note who's not in the guild. (The auslander clergy were marked with a # -- alas, not in scarlet ink.)
Noodling around the online directory and the General Assembly certification numbers to re-set the UUA geographic epicenter -- to come -- I discovered the notation lives, and thanks to a customized Google search can see the list all in one place. More than I would have guessed, too. The term "Non UU" may not be quite fair -- some of these ministers must surely be members of the churches they serve. Some are in federated and multi-denominational parishes; others are in out-of-the-way areas. But not all. Many emerited. An interesting mix.