Are you looking for an official ruling?
Guidelines would be helpful in my regard..
For example Coelestin, Gelasius, Gregory and Martin of Rome are undoubtetly saints of the Russian Church. Others were venerated as saints in the West before the schism, but I have no knowledge (except for the saints of the British Islands approved by Moscow) that their feats/veneration is approved for WR-parishes and lastly, I regard it as problematic to celebrate fests of Roman-Catholic departed (Saints), like John Baptist de la Salle, Pope Pius V., Francis Xavier, Bon Bosco etc., but they are in the RC Missal, and as far as I know, nobody of the responsibles (Vladika Jerome, ..) spoke out restrictions or gave instructions concerning the Sanctorale.
What do you know? What is your opinion?