Yankel,
When you study habad literature , you will see that after each and everyone of their rebeim’s expired name there is a navgam… It seems to me that no habad faction – even those who ostensibly agree that he died – would use this about their deceased leader .
Every sefer of the Rebbe is printed with a shaar blatt that says
“כ”ק אדמו”ר מנחם מענדל שניאורסאהן זצוקללה”ה נבג”מ זי”ע”.
Go into kehos (the official Lubavitch publisher, established by the Rebbe) and look through any of the Rebbe’s seforim.
(This is with the exception of a small fraction of seforim printed by fringe individuals who are constantly in court with kehos for violating copyright. Those say שליט”א)