You're not doing too bad with your reasoning there, however I think we need to be a little more honest with people on the forum regarding the additional firearms related charges. These were added to the Reeva murder case for one reason only - so witnesses could be brought in to discredit OP's character. Without those charges the witnesses would have been unable to appear, due to the incidents being totally unrelated. Nel used a very clever, but very effective method of showing how you can introduce character witnesses to a trial, when they shouldn't really be there. The defense do actually still feel that this evidence was inadmissible, but that's something the judge will have to decide.
Lets remember, the restaurant owners didn't press any charges, they let the matter go. The people in the car with OP didn't press charges. It's not by a miraculous coincidence that these people just remembered these incidents before OP's trial and though 'oh yes, I'd forgotten about that, I'd better press charges'. Nel pressed charges on behalf of the state so he could bring these people into court.
As it happens, I'm on the side of Nel and am glad he used this technique, as I believe character witnesses to previous incidents can be useful. I also think the people should have reported these incidents at the time. In hindsight, his license may have been revoked.