Most likely not. There's already two announced pre-show performers (Austin Mahone and Ariana Grande), and that's more than enough for a 1-hour show that is also supposed to include red-carpet interviews, award presentations, etc.
Maybe they'll perform on the parking lot during the break like Ciara and N.E.R.D. did back in 2010 (No shade, but I agree that they would seem out of place with the rest of the stacked list they have so far, even for their "long-awaited" reunion.)
That makes sense. I could see them being a parking lot performance/house band performance briefly before the commercials
It would only be right for them to perform on the main stage.
People have been hoping for DK to get back together since 2009. It would be one of the highlights of the night.