There is a letter from Rabbi Aharon Soloveitchik who was very affiliated with the litvishe world who writes and I quote: “that the Rebbe could still be Moshiach after Gimmul Tammuz based on the Gemara in Sanhedrin and the Zohar and the Abarbanel, Kisvei Arizal, Sdei Chemed and other sources”. I would like to add that the famous question in Lubavitch is from the Rambam, however, if you look at the halacha carefully in the Rambam, you see that he is talking about “Chezkas Moshiach” and if the person is killed, he loses that Chezkas Moshiach. I think that this could be proven from the fact that the Rambam writes after he enumerates all the things a person has to do to become Chezkas Moshiach. “If he did not succeed to this extent or he was killed, then it is not him.” Would anyone say that if a person leads a war and does not succeed to conquer Eretz Yisroel etc and then he tries again a few years later and he does succeed, that he can’t be Moshiach? There is no makor for that and seemingly goes against Seichel hayoshor. The same is true regarding the phrase..”Or he was Killed”.