The only issue I have with it is that it'd make Elidibus just yet another Ascian - powerful but not much, or at all, different to Nabriales, Lahabrea or Igeyorhm. I have a nasty suspicion that they will make use of such a ploy, but it'd be a waste IMO. My hope is that if Elidibus is taking on Zenos's guise, as is suspected, he is doing something a little more nuanced than simply planning to take control of the Empire with a view to sowing discord, even if that would be a quintessentially Ascian thing to do. Too predictable and boring for me, at this point. He definitely knew what he was doing, though, when he casually gave away Nidhogg's eyes to Ilberd.

Varis appears to be honourable, even if ruthless. He is definitely guided by a moral compass, unlike Zenos. I'd rather not see him die, yet the Prima Vista plotline did seem to make a point of eulogising the previous Emperor in some regards, whilst Varis is painted as more concerned with marshalling the Empire's resources towards war and keeping potential sources of dissent under control. So I do like your idea, but through a catalyst other than Elidibus.