Is it possible to add EDFA and DCM  modules in CWDM  system?

No, EDFA  and DCM modules  can not be used in CWDM system. Since  the EDFA  and DCM modules‘ operating wavelength range is C- Band (1528~1564nm) which can not cover all the CWDM operating wavelength. Generally, the amplifier is used  for DWDM systems.