This is what I was thinking about most of the people listed in that tweet.

Jay-Z is the only person in the list that stood out as a good person to interview. They put out that "Not Guilty" song and two collaborative albums. They also had plans to go on a tour and it fell apart.
https://en.wikipedia.org/wiki/Unfinished_Business_(Jay-Z_and_R._Kelly_album)#Best_of_Both_Worlds_tour

And we all know Jigga man used to be cool with Dame, who was dating Aaliyah before she died.

I don't know what Erykah would say. I remember she referred to R. Kelly as "my brother," or something like that a couple years back when she was hosting the Soul Train Awards. I think she was merely just introducing him. I don't think she supports his actions, but again, what would she add to this documentary? She's not an outspoken artist regarding matters of abuse and sexual assault.

Perhaps dream hampton wanted well-known celebrities to speak out in effort to attract attention to her work. That makes sense, but why not approach someone like Gabrielle Union? To be fair, perhaps dream approached her, too, and she also declined. Gabrielle was very supportive of women protesting that Nat Turner film because of the Nate Parker allegations. Her stance was, "Sis, I understand why you might want to sit this one out. I am a survivor of sexual abuse and I understand."

I had to Google to see if Mary J. Blige and R. Kelly have even collaborated. They have a song from MJB's Share My World album. I don't know what type of history they have beyond that.