Couple quick comments, one subjective and one objective:
S: the colourway is fine, but I don't think the dark blue legends on mildly dark red keycaps look good. I'd do white on red instead (but WDIKAA).
O: You add ISO support in the base kit... but it's incomplete. Enter and short left Shift are present (good), but two alphas are needed as well, one in R3 and one in R4. The image for the base kit, as it stands now, DOES have a couple keys (\| and #~) that could fit the bill, but they're in R1 and are no good (GMK profile isn't flat). Compatibility is pretty good otherwise.
EDIT: I'd also move the 1.75U Shift key from the Hiraganas kit to the base kit.