WP:COMMONNAME is about the title, which is NOT "Orthodox Catholic Church," it is not about the lead. Hence, this article perfectly meets WP:COMMONNAME. The Church's official name is "Orthodox Catholic Church." This is supported by a number official documents of the Orthodox Church, as well as some (few, but some) secondary sources and plenty of tertiary sources. There is no need to "de-emphasize," since there is no better place for the "Official" name than the lead. I will not repost sources, since a good look at the archives will provide sources (primary, secondary, tertiary) that states the official name.

As for the "Google search" (although that type of arguments are not valid in Wikipedia discussions as you all know), here are several websites (I've only included ten since I don't have the whole day), all sharing the same sentence in one way or another "The official designation of the church in its liturgical and canonical texts is “the Orthodox Catholic Church” (gr. catholicos = universal)."
- Orthodox Dioceses of Eastern Pensylvania - 
- Delmarva Orthodox Mission - 
- Holy Cross Greek Orthodox Church - 
- Holy Wisdom Orthodox Church - 
- Most Holy Mother of God (Orthodox ) Parish, which quotes Britannica - 
- Holy Ascencion Orthodox Church - 
- Info-Service - Serbian Orthodox Church - 
- St. Paul Greek Orthodox Church - .
- Orthodox Christian Church in Thailand (Russian Patriarcate) - 
- (Orthodox Church oriented) bookstore - http://www.archangelsbooks.com/orthofaith.asp]

If an WP:RSN is to be started, then there are plenty of references in this discussion page as well as many of its archives that support the accuracy of the "Orthodox Catholic Church" as the official name. They should also be taken into consideration, and not only the three encyclopedia entries.