When we signed with CBS-Sony we were contracted to produce (as I recall) one album a year specifically for the Japanese market. Bob Flick worked with Japanese song-writers to generate our repertoire for those recordings. When we went into the studio we had the lyrics written phonetically and for the most part, I didn't have a clue what we were singing about.
We had to learn a few of those songs to perform in concert and I can only recount my own experience with that process. Interestingly, I recently applied this technique to learning "Lei Pakalana", which the Kingston Trio recorded in Hawaiian on the "Children Of The Morning" album. Basically it's a process of repetition of sounds that have no meaning to me, and that makes it difficult to relate to the lyrics in any way other than simply the phonetics. So I take one line at a time, working up to a whole a verse or chorus, and repeat it over and over until it sticks in my head. Eventually, I get the whole song memorized, tho I have no clue what the words mean.
As for the configuration in this video, you have the personnel correct. I can't remember the specific reason why John Paine was not able to go on that tour - some conflict with his day job, as I recall. He was working as an advertising rep for Kaye-Smith Recording studio in Seattle, bringing clients in to record radio and TV ads. Apparently he wasn't able to get time off. Fortunately, Mark was available and he was a logical fit.
But that beard - wow! Between the two of us bearded wonders I imagine we were quite a curiosity to the Japanese, most of whom are genetically incapable of growing more than a wisp of a beard.