1- Is there really a 'friend' in the vicinity?
Two people in the car with him. You think they just heard gun shots and decided to run over to the dead body and wait for the police to pretend they were in the car with some random guy who is now dead?
2- Which GPS device were they using and what did it record prior to the shooting?
Interesting question regarding the credibility of the witnesses, but if the physical evidence shows the car was moving away from the house, pretty irrelevant.
3- Were they on any drugs/alcohol at the time of the shooting?
Again, could go to the credibility of the witnesses, but otherwise mostly irrelevant.
4- How far into the mans driveway was the vehicle?
Unless it was in drive and heading towards the man, why does it matter? Do you think a car pulling all the way into the drive way gives someone the a reasonable apprehension of serious bodily harm or death such that deadly force in response is justified?