The ESCI figures are no better than toy soldiers/green army men. Nothing that you would want in any diorama. Dragon, Zvezda, and ICM all make Cold War/Afghan War Soviet figures that will be far better for your purposes.
As far as Soviet headgear goes, like any other military, it depends upon the climate, mission, and situation. Soviet paras wear a gream cloth padded helmet for jumps, nearly identical in appearance to the tankers helmet, but with some detail differences. Otherwise they can wear steel helmets, boonie hats, soft caps, or the classic Ushanka. As well as their distinctive blue berets. Boonie hats were seen most in the hot weather and climates of southwest asia. soft caps in warm weather months of more temperate climates, Ushankas are worn in cold weather in nearly all areas, and steel pots or jump helmets as the situation requires. Berets tend to be worn more for garrison or parade wear.