“Well we have the halacha that shlucho shel adam kmoso. Also, remember Shimshon, about whom it is said that he reigned for 40 years although he only lived as a shofet for 20. Why? Because his influence over the plishtim extended 20 years after his passing, and Torah therefore writes that HE ruled the yidden for all those 40 years. So as long as the Rebbe’s efforts continue, he can still be considered bchezkas Moshiach.”
That’s wonderful, but that isn’t Koveah Halacha. Ma Zaroy BaChayim Af Hu doesn’t mean that the Rebbe is considered physically alive in the sense that if we weren’t continuing his legacy, he couldn’t be Moshiach, but now that we are, he can. Halacha simply doesn’t work that way.
L’shitoseych, why do you feel compelled to believe that the Rebbe is already Chezkas Moshiach? Even before Gimmel Tammuz, by a simple reading of the Rambam, the Rebbe was not Chezkas Moshiach. If you want to, you can believe that the Rebbe will be Moshiach, there’s no reason (and no possible way) to say he was Chezkas Moshiach. For the same price, he was Moshiach Vadai.