As far as japanese infantry, the only other types of infantry that I know of would be Kwantung or Manchukuo Imperial Infantry/Guards... I think the Teishin Shudan were a type of airborne marines, seperate from the SNLF (but small in numbers). I'm not familiar enough with these to know if there was a vast difference in uniform appearences, etc to make it worth it. From the few pictures I have seen, they look somewhat similar to IJA infantry, or other animations already available (but not really sure on that).