I've been looking around and I came to the conclusion that BB and Stldetrl are probably the same person. If you compare both channels comments, they were most likely written by the same user... no typos, same 'know it all' attitude.
So, I think that he either knows LM in person or online, Luka could have asked this guy to upload that facial tic video on his account. Maybe LM wrote that description text and asked this guy to publish on the psychology forum that question about the facial tics? Or LM created an account using the same nickname to write the question on that forum. I'm positive that the message looks like it was written by Magnotta. But the video was uploaded on that guy youtube account(Stldetrl who is possibly Beavis Butthead). Maybe he is some online buddy or real life acquaintance, IDK, but there is something odd in this whole thing.
I think it is interesting that in old comments this guy knows a little too much underground details about musicians and music, is almost like he is a musician himself or some journalist, hairdresser, someone in the bizz lol and it seems he travels around, he said he lived in london in the 80s and knew A-Ha band members. Said one of them is bald (I never heard of that before) and bissexual and like anal things, why would anyone mention such details out of the blue? sounds almost as bizarre as Lukas comments.
Now go check Beavis account and read his comments on the video he uploaded about Jun Lin with tons of pictures. Google "Jun Lin as he lived " video. He wrote that JL had a hair transplant and was selling everything, was desperate for money and posted a photo of his credit card scanned with pin code. I don't like the vibe, if he is just some troll, I hate his trolling, is not funny IMO. Makes me wonder if he knows LM on a personal level, maybe he was some prostitution client, hair transplant surgeon, mailed the body parts, kept the head, paid for the snuff video, heck he could be the other guy who owns the snake, maybe he traveled with Magnotta around the world or met him on the webcam. Well you get the idea, I'm curious and I think he is a bit more than your average troll. (of course all here is just my opinion)