no, just because the case is dismissed in the criminal court has nothing whatsoever to do with civil liability. Totally different standards of proof. Immunity from criminal prosecution is something granted by the prosecution in exchange for testimony.
FL Statute 776.032 provides immunity from prosecution for justified use of force. If found, the immunity extends to immunity from civil action, and an award of defense fees against anybody who sues you anyway.
There is a process in FL law for hearing a motion for a finding that the person who used force, is immune under the provisions of FS 776.032. The Florida Supreme Court, in Dennis v. Florida (2010), held that the statutory immunity hearing is one where the court must hear evidence and weigh competing narratives. If the judge finds that the use of self defense was justified, to a standard of proof of more likely than not (preponderance of the evidence), then the defendant meets the requirements for obtaining immunity.
If a defendant is denied immunity, he can still argue self defense at trial. But, lacking immunity, he is at risk of criminal conviction, and he is at risk in civil court.
In the criminal case, self defense is an affirmative defense, raised by defendant. He puts on his case, then it is up to the state to disprove it. The burden of (dis)proof here is on the state, and the state must show that defendant's use of deadly force was NOT justified, beyond a reasonable doubt.
And, as you know the civil court is about the same, except the standard of proof to obtain a wrongful death money judgment is preponderance of the evidence, rather than beyond a reasonable doubt.
-- Immunity from criminal prosecution is something granted by the prosecution in exchange for testimony. --
Yes, that form of immunity also exists, as does immunity granted by Congress or a legislature, again usually in return for testimony against bigger fish.
But in the context of the Zimmerman case, "immunity" is a reference to FS 776.032 immunity for justified use of force; and "immunity hearing" is a reference to a hearing conducted to the standard of Dennis v. Florida, to determine whether or not a person who used force, did so within the boundaries of Florida Chapter 776.