In the past when I have heard missionary transmissions they seldom use an official callsign. I used to tune into the Catholic Mission HQ on South Tarawa in Western Kiribati when I lived on the tip of South Tarawa at Betio and they used to just say "Abemama, Abemama, Abemama, Tarawa." Abemama is south of Tarawa. If they were to use the local licence it would be "T3" prefix.
Likewise, for the 8.076MHz people, they would use an official "P2" prefix for Papua New Guinea, FCC has no jurisdiction over missionary postings abroad as it would fall under "local" licensing and spectrum management under the Communications Ministry of government.
Regarding the SAC frequencies I have heard the ones you have listed, especially 8.992MHz USB which is strong here, also logged SAC on 15.015MHz I think and also on 13MHz somewhere if I recall. Thinking back one of the transmitters is at Anderson AFB and there used to be on at Hickham AFB way back.
In 1983 I visited Anderson AFB near Yigo, on Guam. They have a preserved B-52 Bomber on static display at the base entrance, had a good look over it and toured most of the base, impressive. When I was on Majuro, in the Marshall Islands I also had the courtesy of a base tour of Kwajalein Atoll, a little USA in the Pacific, in contrast to nearby Ebeye where the "domestic" Marshallese workers live in absolute filth and poverty in a gorssly overcrowded "shanty town" type of living. They used to test fire missiles from California to land in the Kwajalein lagoon in those days.
Some place in my documents section I have an article I copied off the net in PDF telling the SAC story and what the transmissions mean and a huge list of frequencies, interesting read.
Will keep an eye on 6.707MHz as it's caught my interest. Could be a fleet operating off the west coast of USA too complete with a mother ship for snap freezing and possibly canning the catch too so you would hear it better than here. Those big trawlers are raping this planet of fish stocks, which are now at historic lows, cannot go on for ever, which is why those huge Spanish trawlers are sneaking around here as the Atlantic has been raped to the max.
Once I was in Pago Pago, American Samoa and I watched the huge Purse Seiners, complete with helicopter on board, discharge their catch at Van Camp/Starkist plants, my goodness they can hold some fish in those holds. Little wonder we are running out of fish...
Nothing at all heard on 6.707MHz from 0720-0815z this evening, not a whisper. WLO beacon on 8MHz 589 report so band open across your way, nil on 6.900MHz.