Chossid, you ask some very good questions. I refer you to the Rem”a by hilchos erev rosh hashana that paskens that you should NOT daven to the meis in the kever, rather you daven to Hashem. Moshe Rabbeinu was Hashem’s shaliach, but the Jews didn’t daven to Moshe- they davened to Hashem. A rebbe teaches you the way of Hashem, but like the Rambam says in hilchos avoda zara, davening to anyone other than Hashem is avoda zara. I’m not a gadol so it’s not my job to know the answers to all the questions. But I do know that gedolim called chabad as it is today avoda zara so I should stay away. You can passel a few of them but you can’t passel all of them. Safeik avoda zara lechumra.
I feel bad for you, Chossid. Since your grandparents weren’t Chabbad you’re not gezhe (The Lubavitch word for meyuchas, ie the families which were from Russia) , which restricts your ability to get good jobs within chabad. If you’re going to drink the Koolaid (Flavorade really but Koolaid is more popular , sorry Jimmy Jones of Jonestown) you should at least earn the good job for it.