Work in progress image
The differences in para vs army units were the padded helmet without flared edges, the jump smock and a folding rifle (you should be able to see the folding mechanism mid rifle shaft).
While the IJA and IJN both had para units, the army was the more active of the two, dropping in a lot of places early in the war. While it looks like original doctrine followed German lines (dropping only with pistols and grenades with all other weapons in ammo crates) it appears the Japanese changed to soldiers dropping with weapons, though I still need to do more reading as it's not entirely clear. The Army was involved in several drops in 1942 and were involved in the fighting in the Philippines in 1944 though I'm not sure it included drops.