The continued allegations of white supremacist propaganda in this thread are without basis, and irrelevant to the discussion at hand. Until some evidence is availed that substantiates these allegations the forum should temper these.
I just read over the Crimes Against Persons statutes of Georgian Law, and due to the passage of the Senate Bill legalizing the brandishing of weapons in disputes, there is no credible basis to accuse the McMichaels of Aggravated Assault. I'm amazed they were arrested on that charge, but of course, this case is emotionally and politically overcharged.
The legal question should fall to §16-3-21-(b)-(3). McMichael is disqualified from a reasonable claim to self-defense from Arbery's advance and attack on him, including attempted seizure of his weapon, if he is deemed the "aggressor". The video shows that he isn't the aggressor in the final physical altercation resulting in Arbery's death, so I would have expected the prosecution would accuse the McMichaels of Simple Assault, a misdemeanor, resulting in Arbery's "reasonable apprehension of immediately receiving a violent injury." Subsequently, you might argue one of two things. The first would be that this could then be argued to escalate to the level of an aggravated assault, since the assault involved firearms, but none of the language requiring that escalation in the statute favors this. Everything would depend on proving the McMichaels threatened him with the weapons in an offensive manner, and that isn't surefooted. Rather, it would seem more cogent to argue the second strategy, which is that this Simple Assault immediately disqualifies Travis from the right to self-defense (including lethal self-defense given his reasonable fear Arbery would have used his own gun on him) because guilt of a simple assault would construe him as the first aggressor.
He would be disqualified if he was in the act of committing a felony, but a false arrest, unlike a false imprisonment, even by a citizen, such as a security guard, even one in possession of a potentially deadly weapon (such as cited by the codes for Aggravated Assault), is not a felony. It also doesn't appear to entail an assault if detention is the only transgression. It is a crime, and Arbery could have pursued civil damages against the two. They also could have faced up to 1 year in jail.
After reading this, I'm suddenly convinced the McMichaels have a case for a stand your ground self-defense claim. I previously believed this was off the table, but it shouldn't be.