I believe that the Chickering imperial cabinets are also each one-of-a-kind.
I can understand a team or individual commissioning a photography studio to create a commemorative set as gifts, resulting in a unique group of cards, since the studio would have been paid for its work. But those issues which advertise a product and yet appear to be impossibly rare are more of a mystery. Unpopular brands and limited distribution explain the dearth of some, but not all, of these issues.
Some of the issues we are talking about seem similar to Tango Egg cards. A plan was hatched
, some cards were printed, and then something happened that changed the plan.
The N167s seem to me to relate to N172 the way 1951 Topps relate to 1952 and onward Topps. An initlal small-scale run followed by a major change in design and an extended run, with smaller tweaks in design, over multiple seasons.
Another obscure issue is J.U. Stead.
My guess is that these are another set of one-offs from a photography studio unless somebody out there is aware of multiple copies.