I don't think the stipulating was of any real consequence at all, because all that was on the table was stuff that was OBVIOUS, making a hearing on it completely pointless.
ITEM 1 - Was there an accomplice involved? Given that she was found guilty of "conspiracy," that was a given.
ITEM 2 - Did her crime do harm of some sort to the family of CV? Given that she killed him and they had testified against her, again, nothing to really decide here.
Knowing that, I think LVD stipulating wasn't about Kay and others getting a chance to speak or not, but rather that there would have been no way for her to win by such a hearing. She wouldn't have said anything, just listen. The outcome was already certain. Being a complete narcissist, what could she gain by forcing other people to say bad things about her? So she said, "No thanks, let's just go on" which was her right.
It's great this was all put to bed, with her found GUILTY to the max, and nothing left for the jurors to have to bother with.