In Florida First Degree Murder is divided into two groups, premeditated murder and felony murder.
Since premeditated murder would require a confession or some sort of evidence that clearly shows the shooter's intent before the fact (a murky possible epithet hardly counts), it's unlikely this guy can be charged for that.
Felony murder, however, requires proving at least two crimes: the commission of a felony and the commission of a murder while committing that felony. There are plenty of felonies to choose from--aggravated stalking is one of them--but because the defendant's protectors have done such a good job of tainting the jury pool and steering the public debate, a two-step trial may be considered too difficult to win.
The Stand Your Ground bullshit doesn't even need to be debated to cast doubt on the success of this path--it is the high-level influence present in this case from the moment the shooter was sent home from a crime scene with the murder weapon. The chain of evidence is ruined, the forensic investigation is ruined, and now if the shooter doesn't confess himself, it's going to be a pain in the ass to charge him with anything.
Second Degree Murder is easier to prove, but it will also have its problems. The shooter cannot be charged with Felony Accomplice Murder because he was not an accomplice nor did he have one before the fact (he certainly had them after the fact, but they were cops engaged in a cover-up).
Which leaves only Murder with a Depraved Mind:
Murder with a Depraved Mind occurs when a person is killed, without any premeditated design, by an act imminently dangerous to another and evincing a depraved mind showing no regard for human life.
The primary distinction between Premeditated First Degree Murder and Second Degree Murder with a Depraved Mind is that First Degree Murder requires a specific and premeditated intent to kill.
It occurs to me that since Depraved Mind appears to be open season on a defendant's character, the course chosen here is designed in part to deeply damage the defendant even if his excellent connections are used to fuck up the investigation, chain of evidence, and trial (as I mentioned before the first thing the defendant's family did was attempt to taint the jury pool, probably in hopes of getting off on the Oliver North technicality, so I think we can expect Z's allies inside the force to drop the ball on the investigation repeatedly).
It may be designed to place pressure on the defendant and his defenders, to elicit a confession and a plea bargain before the trial begins, an approach more realistic than the public wishes, but also an approach which appears to factor in the defendant's powerful influence and high-level manipulation.