From Ch. 24:

That was when Father had told Draco about the Rule of Three, which was that any plot which required more than three different things to happen would never work in real life.

Father had further explained that since only a fool would attempt a plot that was as complicated as possible, the real limit was two.

Your plan is unworkable, because the probability that everything needed for the plan to happen would happen is too low. HPMOR!Voldemort is not a fool, so he would not have planned an unworkable plan (and, as Hat and Cloak, advised Blaise Zambini not to try such plans). Therefore this is not Voldemort's plan.