Neville: “those who believe the Rebbe dies and is still moshiach are making a mistake but aren’t apikorsim, unlike the ones who say he’s alive.”
Source for this distinction? Why would it be worse to believe he’s alive and hiding somewhere?
Crazy? Yes. But, I don’t see why it’s halachically worse.
Nevile, The source for that is both Rav Menashe Klein zt”l and yblc”t Rav Aharon Feldman shlita. As mentioned, many do take the atzmus thing literally, where the Rebbe is c”v “G-d in human form”. Many don’t Baruch Hashem, though how they deal with the Rebbe saying “it’s not a problem asking to Rebbe instead of Hashem because he’s the essence of G-d in a human body” is beyond me.
Almost all Lubavitchers believe the Rebbe is moshiach. If you believe he died, then you believe he’s moshiach but an ordinary human being. If you call him alive, you are ascribing to him deity-like powers to evade death beyond mere mortals. Both of those sources can be found by googling.