No meaningful probability, no. I believe he'll be acquitted. He won;t ask this judge for a finding of immunity, but he will ask the civil court judge for a hearing and finding of immunity. He'll probably win that, and whoever sued Zimmerman for money damages will have to pay Zimmerman's legal fees, lost income, etc. for suing him.
This could possibly be where the “stand your ground” law could come in play, which exempts Zimmerman if deemed applicable?