The Society traces its roots to Archbishop Luis Castillo-Mendez who was ordained to the episcopate by the late Archbishop Carlos Duarte-Costa in 1948, 3 years or so after Duarte-Costa had been excommunicated (and about 5 years after Castillo-Mendez himself had been excommunicated for establishing a separatist Catholic Church in Venezuela). It's never been precisely clear to me when Castillo-Mendez actually established the Society but it had its origins in Brazil, to which Castillo-Mendez relocated after consecration and where he eventually succeeded Duarte-Costa.
Just when the Society separated from ICAB/ICAN (Duarte-Costa's Brazilian ecclesia), I don't know. There's very little information available to suggest that it had much, if any, existence outside South and Central America or the Philippines until after Archbishop Bell (a UK resident) was consecrated midway through the last decade.
Although I didn't notice any specific reference on its pretty extensive website, the Society may well be a constituent body of The Worldwide Communion of Catholic Apostolic Churches, a loose confederation of Churches throughout the world with communal ties to ICAB/ICAN.
As regards the 70 some bishops referenced, the site lists about 35. Several of them are identified as coadjutors, but coadjutors to whom? - there being no sitting bishop identified for most of the sees which have such. (In one instance, there are 2 coadjutors - a fascinating trick if one can pull it off.)
The source of Archbishop Bell's initial presbyteral orders are not identified and I haven't been able to find any details on them but it likely lies in one of the British ecclesia which claim descent from Old Catholicism. The site notes that there was concern as to the validity of those orders and that he was subsequently re-ordained sub conditione by a gentleman identified as a 'Roman Catholic bishop' - though the man's name appears in no listing of Roman Catholic hierarchy.
Bottom line, no prank involved. The numbers are very obviously inflated but, given the Society's Brazilian heritage, and that it has no apparent US presence, it's no surprise that it's not generally known outside the circles of those of us strange folk who keep tabs on the so-called Independent Catholic/Orthodox Movements. Its claim to valid, though illicit, orders is also sustainable in its very direct descent from Duarte-Costa through Castillo-Mendez - with no suspicious intervenors.
That it's in 'discussions' with Rome is not unlikely, as the dicastries maintain ongoing communications with all manner of separatist bodies.
Bell's claim to have concelebrated with the Pope - not impossible. It isn't realistic to think that much vetting can be accomplished on the ground in St Peter's when there are myriad folk garbed in episcopal vesture standing around at the time that a pontifical liturgy is commenced. There's a long-standing but sad history in both the Catholic and Orthodox Churches of pretenders presenting themselves to primatial hierarchs and being accepted on face value as who they claim to be. This accounts in large part for why and how the many papal and patriarchal photo ops occur and get posted on every separatist, independent, and vagante website.
It's one thing to be recognized when you're the head of the SSPX but, when you're the gentleman with a lazy-boy cathedra in your family room - it's easy to pass if you dress the part.
Many years,
Neil