I would say for the Empire of Japan, we could have hulltypes based on the various Japanese cruisers from 1925 onwards, starting with the hull and superstructures of the Furutaka/Aoba classes in 1925, then the Myokos in 1930(?), then the Takaos as the mainline CA hulltype until 1938/39 where we have the emergence of the "Experimental CA Hull" which is probably going to be either Tone or Ibuki, maybe Ibuki as a super CA of sorts and Tone being an offshoot.
As for the CLs, we could have it be smaller versions of said hulls, but as we hit the 30s we get a Mogami hull, since Mogami was really a CL that could be a CA but really shouldn't.