Ortho, still waiting on that shtefanister quote – it seems to be lost and not readily available. You’d think such a thing would be easily accessible, no? I also asked a rov im friendly with whos a rizhiner einikel; he gave me a blank stare for a few seconds and asked what i was looking at online, and that he is shocked that im engaging with such….im not going to repeat the insult…on the internet who could think that moshiach is from the maysim. He said it’s like debating missionaries.
I’m not defining gedolim. The examples you gave, shabsai yzvi(!!!) dovid alreoi, etc… Were not recognized as gedolim by anyone of stature even in chabads circles – does chabad believe that shabsai tzvi was a gadol and that his followers after his conversion to islam and death were gedolim? If they do, then i believe that speaks for itself.
You can name one rishon or acharon whose name is mentioned in any current beis medrash, including chabad, who believed in a dead specific person as the messiah after their death,and I’ll listen. But you can’t, because it doesn’t exist.