did any of the Cast members(Sherman Hemsley,Marla Gibbs And Paul Benedict)Make A Statement About Franklin Cover And Mike Evan Deaths?

I dont think they did

I think you'd have to research contemporary reports. It would depend on whether they were sought out for their reaction/comments by any agency doing the reporting. Heck, TV Guide went to Ann Sothern for reaction to the deaths of both Don Porter and Jesse White in the mid-to-late 90s, a time when her series were a considerably more distant memory than The Jeffersons will probably ever be in our lifetime.