yes, the strelets ww1 russian cavalry would do fine as either side in the RCW. a nice set of infantry might include the greatcoats and fur hats, as well as men in greatcoats with remnants of naval uniforms or czarist trappings. the revolutionary paintings from the period usually showed a mixture of uniforms.

yes it is possible to use crimean wat stuff this is not the same as it is using specially made RCW stuff and the second thing is boxes i would like to have RCW boxes and the third problem is command sets

i really would like to have Russian civil war infantry or command sets in their SPECIAL RCW box