Yah, don't think it will work for most of the jurors. Just trying to guess at the 'shape' of their defense narrative.
They are going to grab onto the state's assertion that not ALL comings and goings are on surveillance footage. So they can possibly get the jury to agree that NOT seeing Kelsey leave is not solid proof that she was deceased when PF was seen leaving with the baby.
It just goes to the dangerous terrain of reasonable doubt.
And it does change the timeline. If they can convince the jury that she was drunk and depressed, she might have sat alone in her condo for 48 hours, without communicating.
And even if he said she was the one who broke up, they can still say it was mutual, but she was having mental issues, etc. I don't think many people would believe that. But it just takes one.