Hey @phil
I made some replies, but it seems they weren’t put up, so I’ll say them again here.
The believe isn’t that the Rebbe wasn’t buried. He was. I believe nearly all of us, except for some very confused individuals, can agree to that. The Shtefaneshter Rebbe said about Yaakov Avinu, that since “Yaakov Avinu lo Mes” he is obligated in mitzvahs. The specific mitzvah pointed out was eating matzah on pesach. So he asks how Yaakov avinu can fulfill this mitzvah. He says there that since Hashem is כל יוכל so hashem is able to give him matzah to eat in pesach in the grave. Now, this isn’t what I think to be the case, but it’s still Torah and I respect the opinion. Rashi says it appeared that Yaakov had died in his commentary on Chumash, and tosefos quotes Gemara in Taanas when commenting on the “Yaakov avinu lo mes” Gemara which says Yaakov avinu laughed after he passed away. The Rebbe says these two take it literally. He also asks some questions which make it difficult to say otherwise. So the Rebbe says Yaakov is alive b’guf. He also says in another sicha that there are others who say Lo Mes Moshe means also bguf, but the Rebbe doesn’t hold by that vort. Nevertheless it is an opinion. The Rif on Ein Yaakov says that Yaakovs כח to move was nullified and they mistakenly buried him. The Rebbe has a letter going through different tzaddikim and sources which say they didn’t die and how there are different levels and opinions. If ur interested in that letter I’ll send the source. The bnei yissachar has an opinion that tzaddikim who never had nanah from this world, on the day of their passing, look like they died but live neshamah bguf. There are also many sources for a guf dak(ethereal second body) which is discussed about many different tzaddikim. Another thing, the Rebbe says the Baal Shem Tov could have lived forever but he chose to die and fulfill the Loshon of the phrase “from dust u shall return”. There is also a famous vort about how the Baal Shem tov and the Maggid of Mezrich visited the alter Rebbe in prison after their passing. One of the chabad rabbanim asked someone who visited the alter Rebbes cell if there was enough room for 3 people, clearly showing he though they appeared in some kind of actual body. When it comes to applying this to the Rebbe it comes from chassidic explanations that moshiach will live forever. These explanations were applied to the Rebbe in 1992 with the chezkas moshiach psak din and that the time for geulah had arrived based on the Rebbes nevuah. They therefore said the oath of hashem that moshiach will live forever applies to the Rebbe. So coming from that direction, we see how it would work. Personally, I went to the Rebbes kever, and put my hand on his gravesite. As soon as I did I felt some type of shock, l’maalah min hateva. My heart felt like it was bubbling and my head was buzzing and there was kinda like a current going through my arm. It was unlike anything I can put into words and lasted until I took my hand off the stone many seconds later. I’m personally telling u this to help bring out that tzaddikim are beyond us and that something is going on down in that kever. u don’t realize the depth of it until u experience the Rebbe, I guess. And no, aside from being sassy my mental health is normal. Altho I can understand wanting to paint me as a crazy anon so as not to have to believe this story. But I experienced it for myself, and I generally tend to keep it to myself but I felt it necessary to say this in context of this conversation.