Well for 1917-1923 you are probably OK using the Copplestone. Brigade Games and Musketeer types.
The collar on the Russian blouse changed to a fall pattern around 1921, and by the later 1920s/ 1930s was universal, so here you are better off using early WW2 era Russians with head swaps. There is some debate as I understand it about the provenance and extent of their issue but certainly there are photos of Soviet infantry in the early 1930s wearing Adrian style helmst adorned with a big red star.
Of course if you are doing winter uniforms, the greatcoat, although changed in detail, won't look too different in 28mm