IANAL, but I don't see how? Isn't solicitation practically the definition of premeditation?
If he asked someone to murder her it was planned out. JMO.
It could be that he wanted her 'out of the way', and some time prior solicited her murder, and that the solicitation attempt came out during the investigation of his actually murdering her. Not necessarily the same event. Hope I'm making sense...
So let's say Perp wants her gone and asks Cousin Nogood months earlier if he would 'take her out' for him. As DA said, there has to be not just the suggestion but some planning for it. They have a few conversations, but Cousin doesn't really think he's for real, just that he's blowing off steam maybe. So he says no to the request, but doesn't report. Then Kelsey goes missing.
In the meantime, Thanksgiving Day no one is around, maybe Perp won't get to see his child for a few days, there's a blow up, whatever, he kills her. This act might not have been premeditated in the sense that he decided in advance it would be on Thanksgiving Day but...
Cousin Nogood comes forward to LE now that Perp is under suspicion. This revelation *could* create a solicitation of murder charge AND, once they discover evidence of death, a Murder 1 charge because even if he didn't premeditate the act *that day* (i.e. even if he killed her in a fit of rage), there's now evidence he *had* been premeditating her death.
Possible.