I know this is mostly off topic and I did some searches but couldnt find anything explaining what the issue is R Dan.
I'm a big chabad fan, went to a chabad shul for years plus some gan izzy as a kid, and stayed in the chabad yeshiva in tsfas several times and ate with the peeps, who all were very believing in the Rebbe being mashiach. And i respect their opinion (though i disagree), but is there any actual split in the real governing structure in chabad (assumedly some believe and some dont, but they can work together), or is it like u say that maybe there are now 2 different hierarchies in chabad, the meshichists and non-mashichists and they dont hold of each other? If so, who has more power/who controls 770?
The so called split in Chabad should not be described as 2 parties, mishechist or not and everyone's one or the other. It's more like a spectrum with extremes on both ends. There are radical fanatics who insist the Rebbe is still physically alive and walking through 770 each day before and after davening and are ready to physically remove someone who stands in their way and there are also radicals to the extreme opposite who will physically fight the other radicals and go to extremes to make sure the Rebbe is clearly referred to as past tense and nothing of him remains alive. Most people fall somewhere in the middle, inclined slightly to one side. Believe it or not, believing the Rebbe is Moshiach is a given for most of the spectrum, all but the extreme. Saying the Rebbe is still alive is another parsha, and within that, to what extent. Most Lubavtichers will not use ZY"A
OR SHLIT'A by the Rebbe's name. A common all round used suffix would be Nesi Doreinu, which shows that everyone agrees that the Rebbe is still out Rebbe and our Nosi Hador regardless of what 3 Tammuz 5754 means to them. The hierarchy of the official Chabad offices are more inclined to the so-called 'anti mishechist' side of the spectrum, but they don't have any kind of blanket rule that you can't be a shliach if you say Yechi, there are plenty shluchim recognized by them who say Yechi. The many unofficial shluchim around the world open up on their own because mostly they don't hold of the official Chabad hierarchy, in their opinion, they are a disgrace to the Rebbe. Some cases of unofficial shluchim resulted from fights with other shluchim in the area, or the Head Shliach of the area.
The bottom line is, every Lubavitcher still considers the Rebbe, their Rebbe. they turn to him for brochos, they send in a Duch and Pan periodically, whether this means sending to the Ohel or inserting it at random into pages of the Rebbe's Torah or correspondence, they get their answers one way or the next. After the histalkus of the Frierdiker Rebbe in 5710, before the Rebbe accepted the leadership officially, chassidim turned to the Rebbe and asked him how do we now receive the Rebbe's advice? The Rebbe answered, you write as always, the Shver (the way the Rebbe referred to the Frierdiker Rebbe) will find a way to answer! some other chassidim fight over who will be the next rebbe while their current rebbe is still alive, the opposite is true for all in Lubavitch, whatever way you look at it, the Rebbe is still the Rebbe.
Almost every Lubavitcher believes the Rebbe will be revealed as Melech Hamoshiach eventually, some make it a point of publicizing it, some shy away, after all, it's from Gemorah Sanhedrin that every talmid believes his Rebbe is Moshiach. Sanhedrin clearly says Moshiach can be from the dead as well, as Tzadikim will have techiyas hameisim before the hisgalus. There is quite a faction in Lubavitch that openly refer to the Rebbe as Melech Hamoshiach, but never say Shlit"a.
As far as 770 is concerned, the gaboyim in control are community elected (the crown heights community) their position on the spectrum is leaning towards the mishechist side, but there are crowds of the extreme there who practically control the place. They act as if nothing changed, the Rebbe's place is set up everyday three times for each davening, they form a pathway and sing Yechi before and after each davening, they say Yechi after krias hatorah and after each davening, but this is all they do on an average weekday, Shabbos it get's a little more extreme, they set up the table where the Rebbe farbrenged every Shabbos and they turn benches and tables toward it and stand there for at least 3 hours as if the Rebbe is actually farbrenging, anyone who tries to stop them moving benches or talks too close to them.....there are more extreme occasional situations but for the most part it's not too extreme. Very few Lubavitchers steer clear of the main shule in 770, only the extreme "anti" won't ever go to 770.
The bottom line is that not everyone who believes the Rebbe is still alive is that extreme or crazy, there is basis for it, they don't necessarily believe it in the most physical sense, but there are various things they can mean, (a certain mashpia in a yeshiva who is known more as an "anti" confided to me privately that even today, when he sits down to write a Pan, he begins with "Pan L'Cha"K ADMu"R Shlit"a, it's only in such a serious moment when to him the Rebbe is very much alive, that he actually writes it like that) (BTW the Rebbe many times used the term Shlit'a after the passing of the Frierdiker Rebbe among other references, he also never said Ztz"l or any other kind of suffix on the Frierdiker Rebbe, although he did write it) Many Lubavitchers who still say or write Shlit"a do it based on the fact their feeling to the Rebbe that he's very much alive through his children, i.e. chassidim and shluchim, mah zaroi bachayim af hu bachayim. The Rebbe once explained that the proclamation of Yechi Hamelech by the people adds life where it's apparently lacking, the Rebbe said this regarding the Frierdiker Rebbe on the yohrtzeit of the Rebbe Rashab, the day the Frierdiker Rebbe effectively took over.
There's much to be discussed on this topic, ein kan hamakom lehaarich....
