I think if the prosecution thinks DeeDee is solid enough to testify to the contents of her most recent statement, they will claim TM was on the bottom screaming and put her on the stand. However, I do think that is unlikely.
I think one needs to look at this from the prosecution's perspective. How are they going to get a 2nd degree murder conviction if TM confronts and sucker punches Z, jumps on top of him, and beats his head against the sidewalk until he get shot? I don't think they can, so they will have to change the altercation from what Z says happened to a scenario that shows Z had a depraved mind. I think they will come up with whatever story they think they can get away with. (I could give examples of how this has worked in other trials, but it is against the rules.) TM being on the bottom is just perfect for the prosecution, so I think that will be their goal. Whether or not they will go with it depends on what the rest of the evidence shows, and their faith in DeeDee to hold up on the stand with a not so friendly attorney asking the questions. When it is all public, we will be able to see which direction they are going. In fact, they will probably leak it. However, if Z's statements are kept under wraps until trial, there is no way of knowing for certain much of anything.