Appreciate the break down brehThere's state guidelines in Florida that may be different in CA, but pretty sure the state can retry at least 3x. But, they usually don't go more than twice. He does not get to go home yet.
The reason he would plea is because they will have info on how many jurors were between him and life in prison. Say it was only 2 jurors, who just wouldn't listen to reason. 10-2 jury verdict means he came within 2 idiots of doing life in prison. Would you want to risk your life on running that again? They will pick a new jury.
Now that both sides have played one round, they know the case better, both sides are bruised, and they may want to just resolve this. It's pretty common.

Goddamn! Was he offered a lesser plea deal and decided to take his changes and ended up blowing trial?No my man's had a mistrial on a murder he didn't do they didn't let him go and he was found guilty at the second trail got 68 years.