After watching it twice and processing everything. This is what I generally gathered even though there's plenty of symbolism and allegories in this episode. OBVIOUSLY this episode is about the duality of Michael Jackson. Even though Teddy and Benny are physically not the same person, metaphorically they are the same individual. Teddy is who Michael was in public, and Benny is who he really was inside; a tormented soul. The fact that Benny was hidden away down in the basement makes it obvious to that allegory of Michael's true-self was pushed and suppressed. Even his true identity was hidden and discarded. Both Teddy can Benny wants to liberate themselves from their pain. Teddy on one hand, needed someone used as a "sacrificial lamb" to murder Benny, liberating himself from suppressed pain that he endured and live the public eye. Teddy on the other hand cannot allow that "public lie" which was Benny to keep on living, he also doesn't want to live himself because of living in torment. This is why Benny killed Teddy and then himself.
Being that this is obviously an allegory to Michael Jackson's last days. To include the daddy issues and all of that, where Darius comes in, from how I see it, is that he plays the role of CONRAD MURRAY. As we recall, Conrad Murray was MJ's physician who went to prison for MJ's death, despite the fact it was per instruction by Michael, himself. What I presume Donald Glover was suggesting was that Michael Jackson was preparing to kill himself and forced Conrad Murray to do just that. Maybe due to him being depressed or addicted, but Darius was the sacrificial lamb just like Conrad Murray.