The bottom three boards are a Japanese layout with ISO English keycaps right? Are the function layers programmable on those? I've always wondered.
I use a Tex Yoda II and operate the function layer with my thumb on the middle trackpoint mouse button so very little movement is required (see image). I have always loved my Topre boards though and would like to replicate this convenience on something using Topre. The Japanese layout with extra bottom row keys and a smaller spacebar seems perfect in theory. It's a lot of money to spend on something I might not be able to use at all if it's not programmable though.
Correct! The bottom 3 are JIS boards. The newer models have a program you can use to program the function layers. The older Pro 2 boards don’t, but you can buy an aftermarket controller that adds programmability. I use Hasu controllers and they’re great. You should be able to get what you want with these controllers.
If you want to find a board with this layout you can use something like Buyee to proxy ship a used one or buy the newer model that’s programmable stock.