OK, I received an email back from my teacher.
It seems that there was a group in the New England area back during that time, who largely came in from other arts. They trained into the Tracy system and then taught that for a while. I guess they were kind of an isolated group, and eventually they largely drifted away and no longer maintained connections with the Tracys.
My teacher never knew the guy, and he asked Al Tracy if he remembers Richard Griffin. Al remembers the New England group, but does not remember Richard Griffin specifically.
Back during that time, the Tracys were not keeping as accurate records of all their members. So if someone from that era drifted away, it is not surprising that their name never made it onto the lists that were compiled later. That is probably why his name is not on the website.