Disheartening to see the ergodox modifiers are function-specific instead of being generic keys - like with the Oblotzky's assembly kits.
I don't like those ones. There are plenty of non-specfic keys that you should be able to fill most of the layouts with them.
I'm
mostly okay with the keys you've chosen. But I find R3 tab to be an odd choice over an R3 control.
However, seeing that there are very few "standard" ergodox layouts that people use (as many users prefer to make their own layouts to suit their own needs) - something along the lines of the novelty legends might make more sense, and reduce the amount of keycaps required for the kit.
A cost reduction and general compatibility increase while keeping the aesthetic is a win/win/win in that regard.