Are you sure he is not one of the Ambassador positions. In Athens, Moscow and Damascus there are representatives present from other Patriarchates. They are there at the invitations of the resident Bishop and are often given property much like an Embassy.
I know in Damascus there is an Archimandrite from Russia, and priest from Athens, Romania and Serbia. In Moscow the representatives from Athens and Antioch are both Bishops and America (OCA) is an Archimandrite. Last I knew in Athens it was an Archimandrite from Russia and a deacon from Antioch.
Generally you are totally correct regarding hierarchs and priest in ambassador positions. Also, an Archimandrite of Serbian Orthodox Patriarchate in Moscow serving in that status has been ordained to the episcopacy with continuation of present duties.
In the case of Chrysostomos Bakomitros, he has served at the Church of Greece and then at the Patriarchate of Alexandria, ended up joining a non-canonical group without a proper canonical release and as a part of this group joined the Patriarchate of Kyiv. After the death of his superior "Metroploitan" Timothy Kutalianos (spelling?) (1942-2004), Mr. Chrysostomos has been ordained and appointed an Exarch. Unfortunately, in 1998 Mr. Philaret Denysenko came up with the idea of "two independent self-fulfilling families of Orthodox Churches". That idea targeted a creation of (2) independent systems within Orthodoxy, when the communion supposed to exist within each family / system, but not between them. While many people within KP did not like that demagogy, the leadership of KP never denounced such plan. On the other hand such plans are not broadcasted for a long time now.
Chrysostomos Bakomitros is not in communion with the Church of Greece and his appointment has been viewed in Athens as a canonical violation. On the contrary, clergy and laity of UOC-USA (EP) and UOCC (EP) are greatly welcomed in Greece. For example, Bishop Hilarion (Rudnik) of Telmissos, an auxilairy hierarch in Portugal of the Metropolis of Spain and Portugal of the Ecumenical Patriarchate, who may be soon canonically transfered to UOCC, in 1990s had served at Patriarchal monastery Vlatadon in Greece in the rank of the Hierodeacon.
There is still a hope that healthier forces within KP will take over some day, but after the death of Metropolitan Daniel Chokaliuk (1958-2005) that seems more problematic. He was in KP, but he possessed a different vision.
Sorry for the long message out of the major topic.