Since this is EPBT, I suggest adding a second 2.25u Shift (physical compat for 660 layouts), as well as 2× 1.5u Code + second 1u Alt (Mac and OG HHKB bottom row compat) to the base kit.
I also suggest using System or Super instead of Code as the OS key legends.
R2 1.5u \|む, like the other pipe keys, should not have a ¥ sublegend in the top right.
Consider adding a R1 1u = key to the numpad kit.
Accent-colored spacekeys other than 6.25u, 7u and sometimes 2u, 2.25u, 2.75u aren't particularly popular. You should remove the following blue spaces from the spacebars kit: both 1u, both 3u, 6u.
In their place, add 1u, 1.25u and off-centered stem 6u in white, and you'll be good to go.
