CathInfo.com

https://web.archive.org/web/20190619013324/https://giaophanphucuong.org/gioi-thieu/cac-vi-chu-chan-cua-giao-phan-10311.html
Who Was This Mystery Bishop?
Fr. Miller testifies:
"We returned to Washington, D.C., to the same hotel, where a Vietnamese bishop greeted us...his valet at one time. I don't remember if it was in Vietnam or while he was in Rome. These were men he had either been an archbishop to, or had elevated to the bishopric to make them bishops. But they were all Novus Ordo. And they were stationed at Conception, Carthage, Missouri. I think it's called Immaculate Conception Seminary, which is now the Vietnamese home base for a religious community. And I was a little befuddled at that. What are they doing here? Why are they here? Oh, we're going to the apostolic delegate's office. And I said, does the archbishop know this? Oh, he's OK with it, I was told. And I said, Your Excellency, do you really want to go see the apostolic delegate? They said, it'll be all right. By this time, he (Abp. Thuc) knew he was out of control and he was going to be politically careful, guarded."

Was this Bishop Cua who Greeted Them?
Bp. Cua was residing at the time at the Carthage monastery in Missouri with Fr. Thiep and Fr. Dien, and the rest of the members (see photo below of Bp. Cua in Carthage).  It seems like he was also part of the plan.  Bp. Cua had been ordained a deacon by Abp. Thuc in 1941.  However, he had been chosen as an Auxiliary Bishop under PVI when PVI was appointing Communist friendly candidates.  Bp Cua traveled extensively outside of Vietnam, even while an Auxiliary Bishop in Vietnam.  He developed a heart problem, and officially retired as Auxiliary Bishop in Vietnam in 1982.  From then on he lived outside of Vietnam, especially in Carthage, Missouri, during this crucial time in the life of Abp. Thuc. 
Bp. Cua is known to have visited the Vietnamese Buddhist monks in France.  The head of these monks was named Thich Nhat Hanh, and was suspected by some of aiding the Communist government.

https://en.wikipedia.org/wiki/Th%C3%ADch_Nh%E1%BA%A5t_H%E1%BA%A1nh#Explanatory_notes


Center Bp. Cua and at right Fr. Thiep

https://www.catholic-hierarchy.org/bishop/bhuyvc.html






Abp. Thuc with Bp. Cua

Aww cute.
Hanging out with his Bishop buddies.