In terms of heteroglossia, the multitude of voices that lend themselves to this project are all separate entities working together. We have the voice of Sharon Daniel directing the movement of the text. She created this project, so of course anything that comes out of it is filtered through her. That's not to say that the text isn't truthful, just that it is someone's creation. In that sense, the voice of the author is present even in the voices of other "characters." That is, Daniel has picked who to use for these interviews, and what part of their interviews to use.
Part of me wants to say that because of that, ultimately the voices of these women are actually Daniel's voice, but that's probably not true. Perhaps it would be better to say that the voices of these women are amplified because of Daniel. As individual interviews, they wouldn't as effective as they are in this project where Daniel is framing them in this context. We can see heteroglossia at work there, with the different voices working together to create a more powerful text.
The voices themselves and the people behind them are definitely very different. I forgot her name, but earlier in the year we listened to a recording of a woman and tried to pick her picture out of a group of other women. I admit I did the same thing while listening through this project, and my thoughts ranged from "omg, I can't stand listening to her" to "omg, why is she even in here?" The women came from a variety of backgrounds: some from broken homes, some from a picture perfect family, many admitted that their own actions landed them in prison, and at least one who felt she was innocent. I'm having trouble finding it again, but there was a part where someone said that there are too many people in prison who didn't commit crimes heinous enough to warrant a prison sentence. Valerie Beidler said, "it seems to me that women are getting slammed with more time than men for the same crimes." Daniel choose to do interviews with women who would show, through their voices and their back stories, the idea that this could happen to anybody. She picks "characters" who don't mesh well together, in order to make the text more convincing.