I think it will work, since neither the Emperor or Darth Vader mentioned Yoda in the OT. Only the Emperor mentions him in the novelization of Return of the Jedi:
So tell me, young Skywalker, who continued your training?
The Emperor fiddled with her ??fingers on the chair arm, remembering.
-There was someone called... Yoda. An old Jedi Master... Ah! I see by your looks that I pressed a rope, a resonant chord in effect. Then it was Yoda -said the Emperor.