As far as the shooters go, legally I have seen nothing yet that puts them in a righteous light. No matter the black guy's criminal record, or if he had been trespassing, or even if he was guilty of recent burglaries in the area, I haven't seen any information that the attempted detention was in any way legally justified. The GA statute on citizen arrest is pretty clear, and even giving all possible charitable interpretations of the events this far disclosed, they didn't meet the requirements for a legal citizen arrest. Certainly once they brandished their firearms they became the instigators of violence, and Arbery would have been fully justified in using deadly force to resist attempted false imprisonment or even attempted kidnapping, and definitely assault with a deadly weapon.
The retired cop, at least, should have known better.