DY
“Do you think the troubling hashkafos are also common?”
If you would please describe the ones that concern you I could give you my opinion. I would say that according to most folks I have known in Chabad, we agree that the Shulchan Aruch HaRav depicts the behaviors that we are to engage in and how to engage in them. Minhagim are also proscribed based upon the sages and cannot be developed independently.
This said there is a signficant Kabbalistic etiology that informs Chabad Philosophy and one needs to be expert in this area to truly understand the significance of the proscribed behaviors. The ARIZAL seems to have the most influence in this area as an earlier poster suggested.
No-one worships the Rebbe although many ask for his intervention via letters at the Ohel (including myself). I am not wise enough to know how this could work but the belief is that every action on earth has a corresponding effect in heaven.
We love our Rebbe and most of us have at least a picture of him in our homes much like one would have of any beloved family patriarch. No-one davens to it nor would it ever be considered appropriate to do so. The idea of a picture of the Rebbe under a pillow at the Bris does not trouble most of us at all although no-one believes that this act in itself will somehow affect the life of the child. Most would view the behavior in the same way one may put a picture of a deceased grandfather in the same position.